Wow,
I have the same problem!
I use a bluetooth receiver to listen to my songs on my phone and when I use the rear defroster, so much static comes on! Not all FM stations get the static when I use the defroster though.

Hopefully someone can chime in on a solution

__________________
JL
'02 x5 3.0i
-Black on Titanium Silver (354)
-Sports Package
-Smoked LED Side Markers
-Chrome Gauge Trim Rings
-Retrofit AEs (Favorite Mod)
-Front & Rear OEM 4.6iS Diffuser
-Front & Rear Fender Flares
-K&N CAI