Getting Sub-Process ID's using the K2 API

Hello,

I'm trying to find all activities in a process, including those in it's child processes (via IPC). To do so, I need to find  the child process Id's in the K2 API. I know it to be possible with process instances, but I needed to find them without opening an instance of the model.

So, in short, can I do something like:

 WorkflowManagementServer conWMS = Helper.GetWorkflowManagementServer();

Activities acts = conWMS.GetProcActivities(ID);

Only with child process activities returned as well?

Thanks in advance,

Fernando