SonarLE not recognizing Edirol UA-4fx completely

I am trying to run SonarLE with a Edirol ua-4fx. Everything is fine for midi. But when I try to use the audio, everything is a little haywire. When I go to Options>Audio and click on the drivers tab, I see the sound card drivers selected. The ua-4fx drivers are also visible, but they are grayed out and unable to be selected. The sound card is a Asus Xonar dx, and when I disable it, the ua-4fx drivers are active and selected. This is extremely frustrating and I have done all that I can think of, including tech support from both companies, but all to no avail. Out of desperation, I switched the driver mode to MME(32 bit), and I can now record both Midi and Audio. Is there any reason that is not a good idea? Is there anything else I should try?