how to add id field to table holding just a list of Strings?

This is my hbm.xml
<list name="versionList" table="versionList" cascade="all" >
<key column="parentComponent_id" />
<list-index column="parentComponentOrder" />
<element column="version" type="java.lang.String" />
</list>

this creates versionList table with three columns: parentComponent_id , parentComponentOrder and version.
Apart from this I want to add unique id generator field to the table.

Hibernate 1 had some feature as specified in http://www.xylax.net/hibernate/toplevel.html

How to do in hibernate 3?

Thanks,
Hari Sujathan

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="mySystem.valueObject">
<class name="mySystem.valueObject.PriorityVO"
table="PRIORITY">
<id name="idPriority" type="java.lang.String"
column="IDPRIORITY">
<generator class="assigned"/>
</id>

<property name="bobsPriority" type="java.lang.String"
column="BOBS_PRIORITY" length="1"/>
<property name="Standard" type="java.lang.String"
column="STANDARD"/>
<property name="missingPri" type="java.lang.String"
column="MISSING_PRIORITY"/>

</class>
</hibernate-mapping>

In this example the String idPriority is the primary key. It is labeled "assigned" meaning that the java code will generate it. That makes this table a table of strings with one string randomly selected to be the id. In your table, you would make it the primary key.
Hope this helps