Hands-free phone calls when hooked to car aux port?

[drewski67]

Hi, I've seen a similar discussion here for other HTC models, or for the TP1 with BT, but not for the internal mic. I have my TP1 plugged into my 2008 Mazdaspeed3's aux port. I did have to use a 3.5mm cord with a filter to eliminate the interference, but other than that it works fine. When I get an incoming call, the ring and the caller's voice are loud and clear through the car speakers, but the internal mic is disabled. Any idea how I can just answer the phone as-is for true hands-free? If there is a software trick for this, I'd prefer to use that, but I wouldn't mind buying a separate mic if that's the only solution. I don't want to use the BT. Thanks!