Since you are still looking at this, you should probably look at these threads and others on Content Center (CC)
http://discussion.autodesk.com/thread.jspa?threadID=517250
http://discussion.autodesk.com/thread.jspa?threadID=514248
There are many here who shy away from CC.
We use iParts. Needless to say iParts and Vault are another headache in themselves.
To make changes with iParts, you need to create a non-Vault Project (Library-Edit) that directly accessed the library folders as a workspace.
When adding Vault to the mix, you need to check out the parent in Vault., switch to the Library-Edit Project, and update the parent, then create or use an existing dummy assembly to update all the children. Switch back to the Vault project, open that assembly, check out all the children, make sure they have all updated properly, then check in all the children and parent.
There are a few posts in the Vault discussion group about this. One or two have some good general information papers on Vault and Libraries which were MUCH better than help and documentation that came with Vault 4.
Pete