I found this on the hibernate user forum:
http://forum.hibernate.org/viewtopic.php?t=943465&view=previous&sid=0148b7cad04e2a4a269c84f5f6e145e3
for v3 change net.sf to org.hibernate.
<property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
<property name="hibernate.dialect">net.sf.hibernate.dialect.InformixDialect</property>
<property name="connection.driver_class">com.informix.jdbc.IfxDriver</property>
<property name="connection.url">jdbc:informix-sqli://192.168.0.89:1527/proyecto3:INFORMIXSERVER=ol_sistemas2;</property>
<property name="connection.username">XXXX</property>
<property name="connection.password">XXXX</property>
<property name="connection.pool_size">1</property>
<property name="statement_cache.size">25</property>
<property name="proxool.pool_alias">pool1</property>
<property name="hibernate.show_sql">true</property>
<property name="jdbc.batch_size">0</property>
<property name="jdbc.use_streams_for_binary">true</property>