From my understanding so long as there are BDA drivers for the DVB-S2 card then Win7 Media Center will support it. So just search for a card which has BDA drivers and has DVB-S2 and you should be good to go (presuming the channels are unencrypted).
I don't know in that case I'm afraid, hope someone else can help.
The issue that MC has is inthe way it scans for channels.. DVBS all the info is there for a scan to produce results BUT DVBS2 isw different and needs input values to scan the transponders and this is missing. The card mnf should be able to get round this with an update likely a reg fix to enable a DVBS2 scan to work.
Some users have dvbs2 channels working as MS has predefined lists and some dvbs2 channels are included in it.
If youhave a hauppauge card they are looking to have a fix of this by the time win 7 is sold .....
You need to speak German, and register to get those derivers.. I have written a bit about how to get connected with the Skystar HD and Windows 7 and included the drivers for download here:
http://www.adfrad.com/2009/10/windows-7-and-technisat-skystar-hd.html
Enjoy :)