Streaming online and in need of help

First of all a big hello and loud and proud shout out to the community. I am in the process of streaming a radio show online. From everything that I've read it is a easy procedure, the problem I'm having that someone might be able to assist me with is that I have a Creative Sound Blaster X-Fi Extreme Gamer sound card that doesn't appear to be mixing the wave and Mp3 files. The result is that you can hear my voice clearly but the background music is at a lower volume and sounds almost muted on the online playback. Is there a specific configuration I should be using? Shouldn't the mixer that came with the program clear this up?