Windows 7: trouble having the default card recognized

I have the Gateway SX2850. My TV is connected through the HDMI output. If I select the HDMI to be the sound out default, everything works fine. However I added a Creative X-FI external sound card. When I make this card the default, I get no sound in recorded or live TV on Win. 7. However, I do get sound on any internet video (like HULU). I'm using a Homerun dual tuner with the sys. What do I need to do to have recorded and on air TV recognize the default that I set. By the way, if I start with HDMI as default, and play live TV, then switch the default sound while the live show is on, I do get the sound. But the next day the live TV will produce no sound unless I set the default back to HDMI.?? Any suggestions appreciated. Thanks.