1. Afaik that card doesn't have a digital out, does it?
2. The card is only 4.1 and not 5.1, but if your receiver has analogue input for front and rear speakers you can connect that at least.
3. If your receiver can mix 4.0 to 5.1 I suggest you use that. It's not real surround, but it's as good as it gets with that card.