Setting a process variable within a subprocess

[turgayz]

I have a process definition, which includes a callActivity. Within the subprocess, I want to set a variable in the parent process instance, is this possible?

In the subprocess, there is a userTask, for which a timer is attached. When the timer goes off, it triggers a serviceTask.
For this serviceTask, I extended ActivityBehavior. But execution.getParent() is found to be null when the service task is executed.

Thank you,

[jbarrez]

Since beta2, you can search for sub/super process instances using the ProcessInstanceQuery