routing audio on XP w/ Echo MIA MIDI soundcard

I want to send a stereo audio input, say a song playing in iTunes, into Max/MSP and control the left and right volumes with Signal Faders. Seems like it should be simple, but...

I have an XP machine with an Echo MIAMIDI sound card. When I try to route audio through Max/MSP and back out to the sound card, it gives me feedback.

I've set up the Max DSP settings thusly:

Input Channel 1: Mia analog 1
Input Channel 2: Mia analog 2
Output Channel 1: Mia V3/4
Output Channel 2: Mia V4

I made a simple patch (see below) to accept the audio in and send it to 2 faders, then back out again.

In the Mia console I can see Analog In signals 1 and 2 on the meters, that's the iTunes input. I also see the Virtual Out 1, 2, 3 and 4 signals on the meters, as well as the master Analog outs 1/2.

Virtual out 1 and 2 is what I currently hear through my speakers.
Virtual 3 and 4 is the Max output.

The problem is Virtual outs 1,2,3,4 are summing together, but if I mute Virtual outs 1/2 to prevent the output from being doubled, all the other Mia channels turn off. This may be a limitation of my sound-card, but I'm wondering if anyone has a similar configuration and has it working, or am I missing a piece of the puzzle?

Here's my patch: