@Entity
@Table(name="tableA",schema = "schemaX")
.... JavaSource .....

<datasources>
   
   <local-tx-datasource>
      <jndi-name>DB</jndi-name>
      <connection-url>jdbc:mysql://localhost:3306/db</connection-url>
      <driver-class>com.mysql.jdbc.Driver</driver-class>
      <user-name>...</user-name>
      <password>...</password>
   </local-tx-datasource>
   
      <local-tx-datasource>
      <jndi-name>IsisDatasource</jndi-name>
      <connection-url>jdbc:mysql://localhost:3306/isis</connection-url>
      <driver-class>com.mysql.jdbc.Driver</driver-class>
      <user-name>...</user-name>
      <password>...</password>
   </local-tx-datasource>
   
</datasources>

..
<persistence:managed-persistence-context name="DBManager"
                                     auto-create="true"
                      persistence-unit-jndi-name="java:/DBEntityManager"/>
                     
   <persistence:managed-persistence-context name="IsisManager"
               auto-create="true"
                      persistence-unit-jndi-name="java:/IsisEntityManager"/>   
..

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
             version="1.0">
             
   <persistence-unit name="DB2">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:/DB</jta-data-source>
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="false"/>
         <property name="hibernate.format_sql" value="true"/>
         <property name="jboss.entity.manager.jndi.name" value="java:/DBEntityManager"/>
         <property name="jboss.entity.manager.factory.jndi.name" value="java:/DBEntityManagerFactory"/>
      </properties>
   </persistence-unit>
   
   <persistence-unit name="Isis">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:/IsisDatasource</jta-data-source>
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="false"/>
         <property name="hibernate.format_sql" value="true"/>
         <property name="jboss.entity.manager.jndi.name" value="java:/IsisEntityManager"/>
         <property name="jboss.entity.manager.factory.jndi.name" value="java:/IsisEntityManagerFactory"/>
      </properties>
   </persistence-unit>
   
</persistence>

<hibernate-configuration>
  <!--  <session-factory name="java:/DBDatasource">-->
   <session-factory>
<property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
<!--      <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> -->
<!--     <property name="connection.datasource">java:/DefaultDS</property> -->
   <property name="connection.datasource">java:/DB</property>
    <property name="transaction.factory_class">org.hibernate.transaction.JTATransactionFactory</property>
    <property name="transaction.manager_lookup_class">org.hibernate.transaction.JBossTransactionManagerLookup</property>
    <property name="cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property>
     <property name="hbm2ddl.auto">update</property>
<!-- <property name="hbm2ddl.auto">create-drop;update</property>-->
   <property name="show_sql">false</property>

... mappings for jbpm stuff ...

<?xml version="1.0" encoding="UTF-8"?>
<!-- Persistence deployment descriptor for dev profile -->
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
             version="1.0">
             
   <persistence-unit name="orderProcessor">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:/orderProcessorDatasource</jta-data-source>
      <jar-file>acquityOnDemand-ejb.jar</jar-file>
      <class>com.acquitygroup.acquityondemand.entity.OrderHeader</class>
      <class>com.acquitygroup.acquityondemand.entity.Address</class>
      <class>com.acquitygroup.acquityondemand.entity.BillingAddress</class>
      <class>com.acquitygroup.acquityondemand.entity.ShippingAddress</class>
      <class>com.acquitygroup.acquityondemand.entity.Payment</class>
      <class>com.acquitygroup.acquityondemand.entity.OrderLine</class>
      <class>com.acquitygroup.acquityondemand.entity.ShippingOption</class>
      <class>com.acquitygroup.acquityondemand.entity.ShippingPrice</class>
      <class>com.acquitygroup.acquityondemand.entity.Sku</class>
      <class>com.acquitygroup.acquityondemand.entity.Product</class>
      <class>com.acquitygroup.acquityondemand.entity.SkuPrice</class>
      <class>com.acquitygroup.acquityondemand.entity.PriceList</class>
      <class>com.acquitygroup.acquityondemand.entity.ProductCategory</class>
      <class>com.acquitygroup.acquityondemand.entity.Category</class>
      <class>com.acquitygroup.acquityondemand.entity.Catalog</class>
      <class>com.acquitygroup.acquityondemand.entity.Site</class>
      <class>com.acquitygroup.acquityondemand.entity.Client</class>
      <class>com.acquitygroup.acquityondemand.entity.CreditCard</class>
      <class>com.acquitygroup.acquityondemand.entity.User</class>
      <class>com.acquitygroup.acquityondemand.entity.UserRole</class>
     
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="true"/>
         <property name="hibernate.format_sql" value="true"/>
         <property name="jboss.entity.manager.factory.jndi.name" value="java:/orderProcessorEntityManagerFactory"/>
      </properties>
   </persistence-unit>
   
   <persistence-unit name="integration">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:/integrationDataSource</jta-data-source>
      <jar-file>orderProcessor-ejb.jar</jar-file>
      <class>com.acquitygroup.orderprocessor.entity.MessageToClient</class>     
     
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9Dialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="true"/>
         <property name="hibernate.format_sql" value="true"/>
         <property name="jboss.entity.manager.factory.jndi.name" value="java:/integrationEntityManagerFactory"/>
      </properties>
   </persistence-unit>
   
</persistence>

package com.acquitygroup.orderprocessor.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Lob;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

import java.math.BigDecimal;
import java.sql.Date;

@Entity
@Table(name = "MESSAGE_TO_CLIENT")
public class MessageToClient {
   
   BigDecimal messageToClientId;
   String clientCode;
   String acquityId;
   String type;
   byte[] payload;
   BigDecimal errorCount;
   Date createTimestamp;
   Date sendTimestamp;
   String locked;
   String finished;
   Date finishTimestamp;
   
   public MessageToClient(){}
   
   public MessageToClient(BigDecimal messageToClientId, String clientCode,
         String acquityId, String type, byte[] payload, BigDecimal errorCount,
         Date createTimestamp, Date sendTimestamp, String locked,
         String finished, Date finishTimestamp) {
      this.messageToClientId = messageToClientId;
      this.clientCode = clientCode;
      this.acquityId = acquityId;
      this.type = type;
      this.payload = payload;
      this.errorCount = errorCount;
      this.createTimestamp = createTimestamp;
      this.sendTimestamp = sendTimestamp;
      this.locked = locked;
      this.finished = finished;
      this.finishTimestamp = finishTimestamp;
   }
   
   @Id
   @SequenceGenerator(name="SEQ_MESSAGE_TO_CLIENT")
   @Column(name="MESSAGE_TO_CLIENT_ID", unique = true, nullable = false)
   public BigDecimal getMessageToClientId() {
      return messageToClientId;
   }

   public void setMessageToClientId(BigDecimal messageToClientId) {
      this.messageToClientId = messageToClientId;
   }
   
   @Column(name="CLIENT_CODE")
   public String getClientCode() {
      return clientCode;
   }

   public void setClientCode(String clientCode) {
      this.clientCode = clientCode;
   }

   @Column(name="ACQUITY_ID")
   public String getAcquityId() {
      return acquityId;
   }

   public void setAcquityId(String acquityId) {
      this.acquityId = acquityId;
   }
   
   @Column(name="TYPE")
   public String getType() {
      return type;
   }

   public void setType(String type) {
      this.type = type;
   }
   
   @Column(name="PAYLOAD")
   @Lob
   public byte[] getPayload() {
      return payload;
   }

   ....
}