You could use the quartz delegating timerservice backend: set the org.jboss.ejb3.timerservice.factory property to org.jboss.ejb3.timerservice.quartz.QuartzTimerServiceFactory.
I'm using jboss 5.1 and i can't find org.jboss.ejb3.timerservice.quartz.QuartzTimerServiceFactory nowhere in the classpath.
The issue i'm experiencing is that i have a thread for every timer scheduled in future.
Any ideas on how to solve that? (Upgrade to jboss 6/downgrade to jboss 4 is not an option for me now)
Thanks in advance,