In all the ibm-jdk packages the SLOT is set to "0". I prefer haveing one version of each JVM installed for product testing. In some cases we still use 1.2 JVMs in production enviroments and it's more convitent to test locally. I would like it if the SLOTs are set like they are in the sun-jdk packages, where SLOT="1.3" or SLOT="1.4" In all of the ibm-jre packages the SLOTs are equal to "1.3", even the ibm-jre-1.4.0.ebuild.
Fixed on portage tree now. Thanks.