I started doing some Hibernate work this week using MyEclipse 6.0 M1 on Eclipse 3.3 (Europa) and I ran into a problem with signed jars which showed the error message:
signer information does not match signer information of other classes in the same package
Apparently JAR are now being signed in 6.0 but cglib and hibernate3 jar files were not supposed to be excluded. The end result is that I can grab older versions of the jars or unjar them, remove the signatures and rejar them.
The other option is to wait until MyEclipse 6.0 GA is released. This release is scheduled for mid-August which means “any day now”. Maybe it will be out this weekend.