Just a quick note to say that after a fairly short time from the release of Exchange 2007 SP1 Rollup 6 another Rollup is available.
Rollup7 fixes quite a number of irritating issues including some with SCR.
It is well worth a look and more info can be found here:
The Rollup can be downloaded here:
Finally, it will be available from MSFT Update on the 24th March 2009.