Deployed archive is locked in JBoss 5.0 Beta2

Deploy an Java5 EAR application by copying it to server\default\deploy\

It will be deployed. Now try to undeploy it by deleting the file => file is in use and cannot be deleted.

I verified it with this EAR: http://www.informatik.fh-wiesbaden.de/~knauf/public/Stateless.ear

The same problem also occurs if I deploy only the EJB jar file from the sample.