18.2 chapter of ejb core says
Timers can be created for stateless session beans, message-driven beans, and 2.1 entity beans.
Timers cannot be created for stateful session beans  or EJB 3.0 entities.
The timer service is intended for the modelling of long-lived business processes. Timers SURVIVE container crashes, server shutdown, and the activation/passivation and load/store cycles of the enterprise beans that are registered with them.
So it turnes out that the Timers support activation/passivation is only for EJB 2.x entites?