WebSphere 6.1 - JMS - ListnerPortNames

During the creation of our prototype of a J2EE solution on Websphere,
we used JMS on a local Websphere installation.

Because of the lack of tools, we created the deployment descriptor by hand.
For the JMS-Communication we defined an activationSpecification in the

All worked fine, but during the deployment at the customer site, they wanted
a listenerPort to be used instead of an activationSpec. So we redesigned
the deployment descriptor. A test of a small demo was successfully at the
customer site.
But after creating the listenerPorts on the local Windows version the application could not start.
There was a problem in the errorlogs, that the listeners could not be started.

The difference is that the customer used MQ-Series as JMS and we used the
delivered JMS-Implementation in the Websphere.
So perhaps the listeners could only be used on external JMS sources,
because the error message mentioned that listeners can not be created on
the default JMS provider.