Memory leaks where the classloader cannot be garbage collected / impossible to dispose tomcat devloader when i reload context (drools keep reference)...

(sorry for my English) We use drools 4.0.7
in a hospital application.
We load drools and our programs (services) with tomcat Devloader
(5.5.9) We use drools in statefullsession (retract and insert facts
by rules in a ruleFlow).
everything is perfect for us, except a little problem of "dispose"
with tomcat due to drools.
Through the Tomcat console when we try to restart our webapp, tomcat
can't dispose the old Devloader (in Eclipse we can see that many
drools class use class attribute ClassLoader without any dispose ???)
In production, we used different webapps in a Tomcat, so we can't
easily stop Tomcat, so until we stop tomcat, the reload of the
webapps is longer and longer ... (many devloader(s) can't dispose)...
anyone has had this problem ?