Hello.
I know the frustration.
My response may not specifically address your exact situation, but perhaps my problem solving and solution may spark a path for you to solve something on your side. Worst case, you'll know you're not alone in such a bind. :s
I use the Studio GT - Active Studio Monitors with USB Audio Interface, (
http://www.samsontech.com/samson/pro...o-gt/studiogt/), which normally works very well. But, if load up POD FARM (a software that emulates various amps and effects for the electric guitar) I get a conflict at the sound card level.
It's like this: both Samson and PodFarm are competing for ASIO's attention, but only one can win. I need Samson to win so I can hear the guitar, but I need PodFarm to color the guitar sound. But... BAM: conflit!
I found a solution, but it's not ideal:
Instead of plugging my headphones in Samson (which is the normal thing to do), I plug them into the output jack found on the side of my laptop. Then I go into Reaper preferences (shift+p) and in the Audio Device panel I set the Audio System to WASAPI (Windows 7/8/Vista). It can also be set to another system, just NOT ASIO. I need to give ASIO to PodFarm (greedy little bugger).
Then set the input to listen to the microphone jack of the laptop, not the USB port (which is the Asio normal routine).
All that is left to do is relay the headphone output of the Samson to the microphone jack of the laptop with a 1/8 jack cable.
I know all this sounds crazy, but one important thing that I've learned throughout my years of playing and recording music is to plug things into other things using all sorts of connectors and cable lines. There is almost always a way around a problem when you start relaying headphone output of one hardware into the microphone input of another piece of hardware, or vice-versa...
Get good at doing this and thinking outside the box and you'll gain a valuable skill set; you'll be the guy that can make things work when everyone else is lost and convince that there is no solution to their problem.