Two EJBs loading identically named package/class from separate JARs

[rob005]

I have an EAR that contains 2 stateless EJBs that each have a Manifest Class-Path attribute pointing to separate JARs.

These JARs contain different versions of the same package/class name.

EAR

      lib

      lib1

         jar1

            test.ejb.Test

      lib2

        jar2

           test.ejb.Test

     EJB1.jar

        MANIFEST.MF

           Class-Path: lib1/jar1.jar

     EJB2.jar

        MANIFEST.MF

           Class-Path: lib2/jar2.jar

When executing EJB1, it loads lib1/jar1/test.ejb.Test and runs as expected

When executing EJB2, it loads Test from cache rather than my expectation of the jar2 variant.

I have tried setting the "Ear subdeployments isolated: true" but that then fails for both EJBs

Any clues/help would be greatly appreciated.