I have integration UCM, the problem is that with one specific user when you add new file to source control and connect with CQ record it says:
This operation is not yet supported for ClearQuest Web connections.
Please use a ClearQuest native client connection to perform this operation.
How to avoid that error message?
It depends on the exact version of ClearCase.
CCRC (ClearCase Remote Client, 7.1.X up to 8.0.1) for example, has quite a number of limitation when integrated ClearQuest (swg21398642).
If this is CCRC, see "CCRC supports the UCM integration with ClearQuest"
If it is not CCRC, then check "Establishing the Rational ClearQuest Web interface", which does mention: