Jim,
I asked about ClearCase a few years ago, when we were looking
at source control in RoboHelp. I was told that ClearCase doesn't
play "nice" with RoboHelp and I think someone recommended Virtual
Source Safe or something similar instead. We ended up using
Robosource Control and then had to abandon it because we couldn't
get a server to use with it (no one wanted to share any part of an
existing server with a Robohelp application).
Jim