signed cglib.jar doesn't work in guice-hello example

the bundled signed jar jboss-eap-5.1.0.CR1.zip/jboss-eap-5.1/resteasy/lib/guice.jar
cannot be used with guice-hello example
when I deployed the war containing this version of jar to EAP, the deployment fails with error message:

java.lang.SecurityException: class "org.jboss.resteasy.examples.guice.hello.DefaultGreeter$$FastClassByGuice$$70fd68d0"'s signer information does not match signer information of other classes in the same package

(see logged-problem.txt for details)

I don't have any theory for this, I just know that this is the issue of signed guice.jar vs unsigned guice.jar, because I tried to isolate this issue in a standalone smaller testapp (no war)
It seems as the CGLib generated class "org.jboss.resteasy.examples.guice.hello.DefaultGreeter$$FastClassByGuice$$70fd68d0" is treated as having the same signer as guice.jar (not cglib.jar, because the combination signed cglib.jar and unsigned guice.jar works) and therefore this conflicts with other classes in "org.jboss.resteasy.examples.guice.hello" which are unsigned.

this would mean that only code with same signer as guice.jar may use this library, which is kinda restraining.