Capture cards and USB capture devices (especially TV tuner devices) rarely work outside of their parent programming. The rule of thumb is, if it will work in chat clients such as Skype and AIM, it SHOULD work in MediaShout. We have been testing and working with a new line of cards from Datapath that we recommend. Check out the Datapath VisionLC capture cards as well as the full line of capture cards from Datapath. They are only Windows compatible and are internal cards, but they have a very low latency and process resolutions better than anything we have seen or tested.
If your ministry wants to use Live Feed, we'd recommend reviewing this article for the best way to accomplish this. You can also find information about connecting your systems in this article.