I guess I post here some of my experience.
I am trying to get a DVB-S2 card from Hauppauge and here is what I had to do... you may have to go through it too.. (all or in parts). Be advised that DVB-S itself is a complicated business.. so you can image complications about S2 business...
Anyway here we go...
A) first you have to get linux to recognize it. After you put the card in, "ls /dev/dvb*" should tell you how many cards have been recognized. If not, then you have to patch the kernel for it to recognize it. I had to patch mine that I got from dvb mailing list. Search for linux-dvb and you will find out whether the card you want will be recognized in kernel or not. If not, then is there a patch or not.
B) you may also need sasc-ng. Google it and you shall know..
C) then comes myth-tv. if you are in North America, you will have to recompile mythtv from source, in order to get disec switch and other support built into mythtv. Then comes configuration (as you may not have all the transponders of the bird you want to scan.. ). There is stuff available on the net. For other places (depending on the signal you have) you may not have to do it..
D) at this point, you shall have DVB-S working. But S2 is also hd. For that you will need a video player that can support mpg4. Not sure if Linux mce + mythtv can do mpg4 (H.264 is the one that has issues.. ). Also you will probably need a dual core cpu with some good amount of ram in order to do decoding, since none of the video cards do mpeg4 decoding for linux (there are some which do that with the help of latest drivers on windoze)
Let me know if you get somewhere as I would to know your experience..
Hope this helps..