Michael,
I'm just reviewing my design options to migrate my JBPM CalDav adapter from JBPM3 to 4. Looking at the TaskService api it seems possible to create a task independent of a process / execution; I want to handle tasks associated with a process and those that aren't. In jBPM3 I use the strategy of creating a very basic process with a single task for standalone tasks. This also works in JBPM4. It seems that sticking with this strategy is the simplest way of dealing with timers in all situations.