Win 8 - How to use StereoMix and Headphones Mic at the same time?

I am using Windows 8 64 bit and believe I may have an IDT driver problem.

I need to enable StereoMix and my Headphones Mic at the same time. I know this was previously possible with windows xp and windows 7.

What happens is If I enable either Headphones Mic (Logitech headphones with Mic) or StereoMix the other one becomes " current;ly unavailable"  I cannot get them both to work together. I can get StereoMix and the Internal Mic to work together ( both enabled at the same time) but the sound quality is bad because the internal mic picks up noises from the PC. I need to have both my headphones mic and stereo mix enabled at the same time.

The driver I'm using is the one provided by HP with the laptop. It is called sp59620.exe

Would another IDT driver solve the problem? Can you think of another reason this is not working?

Here are my specs.

System Manufacturer/Model Number HP Pavillion G7-2251dx
OS Windows 8 64 bit
CPU AMD A-8 4500M
Memory 8 Gigabytes DDR3 sdram
Graphics Card Discrete ATI Radeon HD 7640G with 2 Gigs
Sound Card IDT Audio
Monitor(s) Displays 17.3
Screen Resolution 1600x900

If you cannot help, where else should I look? i have tried Windows and Microsoft forums and no one can give me an answer.

Thank you.