Problem with debugging multiprocessing children

I have a simple producer / worker script using multiprocessing, similar to the worker pool example here: http://docs.python.org/library/multiprocessing.html

I checked the 'Attach to subprocesses automatically while debugging' box, and debugger executes with the following cmd-line:

C:\Python27\python.exe "C:\Program Files (x86)\JetBrains\PyCharm 2.0.2\helpers\pydev\pydevd.py" --multiproc --client 127.0.0.1 --port 58986 --file qTest.py

Breakpoints in the main thread are hit, however breakpoints in code executed by worker processes do not stop execution. Any ideas? Should I be able to debug child processes in PyCharm?

Thanks,

Patrick Marks