OK, I can now close this thread with the appropriate explanation and solution, which off course have nothing to do with Xalan/Xerces.
Please read http://www-4.ibm.com/software/webservers/appserv/doc/v40/aee/wasa_content/060401.html to find out more about Websphere Application Server (WAS) class loading. It looks like the difference between WSAD beta and 4.0 is that the WTE is now using WAS EE class loader options. To solve my particular problem, all I had to do was to set com.ibm.ws.classloader.ejbDelegationMode to false, so that the EJB module would use the module class loader first.... Thanks for your help! Franck
