How do I optimize J.River with quality sound card

I've been doing a bunch of reading on this site and it's been very informative. I'm trying to wade into the PC audio arena and I would like to do so initially on a small budget.

I currently have a two channel setup with a Rotel CD/integrated amp and Linn speakers. I do not have a stand alone DAC and I would like to set up my PC using a quality sound card initially. I read a good article in the Absolute Sound on the subject and the author used an Echo/Mia Midi soundcard and Foobar2000.

I purchased an Echo Gina sound card which has an internal PCI card with a breakout cable to an external box. The external box has a DAC and both analog and digital I/O connections.

After messing around with Foobar, I find the user interface a little lacking. I think J.River is easier to use and I would like to use that as my software.

So, the question is what steps must I take to use J.River and bypass the KMixer in WinXP. Most of the other posts on this subject reference setup with USB DACs. I may go that route one day, but not yet.

Thanks to all in advance. This is a great site.