TypeMock (5.2) + NCover + Visual Studio: fail to cooperate

I experienced this before, but lately it was stable. Looks like I am having this problem again.

Scenario:
- Upgraded TypeMock Isolator to version 5.2 (in fact, 5.2.1 internal build that was sent to us)
- Upgraded TestDriven.NET to 2.18 beta
- Run "Run Tests" from TestDriven menu, works fine, all mocking is done.
- Run "Test with Coverage", NCover fails to generate coverage report.
- Check "Isolator Configuration". It is not linked to coverage tool. Link it to NCover
- Run "Test with Coverage", now TypeMock complains that it is not enabled.
- Check "Isolator Configuration" again. It still is not linked to coverage tool. Link it to NCover.

and so on, and so force. If I don't link TypeMock with NCover, coverage generation fails (and it should), if I link it, first time it complains that TypeMock is not enabled, after that it mysteriously unlinks TypeMock from NCover and then coverage generation fails again.

The problem occurs only from within Visual Stuidio, but it is painful enough.

What can be wrong? I remember I've seen it before.