There seems to be a lot of issues using Skype with professional SDI capture cards. More and more we are getting asked by broadcasters to use skype for lives as a cost saving measure, Al Jazeera, BBC, etc etc.
We are running Mac OSX Lion 7.5, Skype 188.8.131.5268, and BMD Desktop Video 9.6.8 with a Blackmagic Studio 2 card.
Skype has always been an incredibly flakey app. Even with firewire you could only get video and no audio. With the current setup we can get audio but no video. We are feeding it SD PAL over SDI. There are some forums listing information for older versions of skype but mostly on Windoze.