After speaking with DDMtuning, they said I needed this to solve my problems:
http://us.st12.yimg.com/us.st.yimg.c..._2034_18608070

"Warning Code Eliminator
Some cars will generate a bulb out warning message or even turn the headlight/foglights off when connecting HID to them. Our cancellation modules fool the computer in the car and allow the HIDs to work flawlessly."

Received and installed the warning code eliminator today. Now the HID fog kit from DDMTuning works perfectly.

- No flickering at startup (in cold weather too)
- No "check fog lamps" message on the dash

I'm very happy with them now that they work properly. I recommend this mod - just know ahead of time that the total cost will be more like $100. Easier mod for post-face lift because there's no cutting required of the fog light assembly.

Thanks to Mister2 for turning me onto to these!