Creative Soundblaster X-Fi Surround 5.1 Pro USB Audio System with THX SB1095

I'm assuming that all you who own an X51 know by now that the sound cards used don't support Dolby Digital Live and therefore only play DVD films in 5.1. This is a huge problem for gaming because that means my center speaker is left out of the sound equation. I've noticed that when I play a game the AI conversations will suddenly drop if you turn your back on them. You have to be facing them or you'll completely miss the dialogue.

To the point, the title of this post says it all. I wanted to get a simple USB external sound card that will play my gams in 5.1 THX...Anyone have experience with using external sound cards for gaming on the X51 and have you experienced problems doing so?