You'll have to edit the scripts on the client machine to kick off VSS on additional drives. Then you'll edit the rsyncd mount points accordingly.
If I recall, the applicable files are backuppc.cmd, vsrsync.cmd, and rsyncd.conf
There are also differing versions of vshadow depending on your client OS (
http://edgylogic.com/blog/vshadow-exe-versions/). I just include them all and edit the scripts to choose accordingly.
Also, bear in mind that Michael's solution isn't really meant for in-place restores (you can alter it to do it, but this can potentially cause more trouble than it's worth). But 99% of the time we only have to restore a single file so it's easy enough from the web interface.