This is the last remain bug in the 3.0 testsuite.
It is fixed in 4.0, but the fix is quite major.
I've tested it with 3.0 and it does work, but I need
to convince myself that it doesn't break other things.
I'll probably apply to the 3.2beta first.
Thanks for your answer
I suppose I can live with this bug until the 3.2 release.
It seems it also happens with wars referencing jars through MANIFEST.MF or even simple jars referencing each other but it should probably be the same bug