I attempted to debug as suggested but I ran into a problem: Presumably because I had installed VS without MSVC there was no option to attach to a running process. The installed MSVC++ Express does not allow attaching to running processes.
I decided to clean-up my install and deinstall all my legacy VS components and reinstalled VS 2010 with MSVC to be able to attach to a running process. Now, debugging is available!
I see two possibilities:
1. the debugging functionality needs MSVC installed as part of VS
2. the debugging functionality somehow conflicts with the other VS components (MSVC Express & legacy)
Many thanks for your help!