Workspace creation and configuration programmatically, possible?

[john]

Hi,

I'm trying to create a workspace in my repository with a different 
persistence manager than the default which use Derby DB.

workspace.createWorkspace("thename"); works fine, but how I can do to 
change that in workspace.xml (before initialization)only using Java code?

 <PersistenceManager 
class="org.apache.jackrabbit.core.persistence.pool.DerbyPersistenceManager">
          <param name="url" value="jdbc:derby:${wsp.home}/db;create=true"/>
          <param name="schemaObjectPrefix" value="${wsp.name}_"/>
        </PersistenceManager>

I want to use :

org.apache.jackrabbit.core.persistence.bundle.PostgreSQLPersistenceManager

If it's not possible to affect one different value for each working set, is 
there a way to change the default value when repository is not yet 
initialized/created ?

Thanks