Below is an e-mail from THB, the licensed makers for Treo 600 car kits:

Hi (name withheld),

I apologize for the late reply. We took a direct hit from Hurricane Frances and have no power. I am borrowing a generator for a few hours to catch up with my emails.

Here is the miracle patch that should solve you incoming call no audio issue! THIS PATCH IS ONLY FOR SPRINT AND VERIZON CUSTOMERS EXPERIENCING NO AUDIO DURING INCOMING CALLS!!!!

Please do the following:
Hotsync this PRC file onto your Treo 600. Immediately after the hotsync operation is complete do a soft reset and then turn the phone on and try it out in the car-kit. Please let me know if it seems to be functioning properly so I can report back to PalmOne with your feedback.

Thank you for your patience and understanding during these difficult times.

Best regards,
Alan Jarvis
National Service Manager

384 SE Greenway Terrace
Port St. Lucie, FL. 34983
Office: 772-336-2944
Fax: 772-873-0073
Cell: 786-271-2501

* This by the way is not the CDMA patch in the Palmone website. So if anybody has a problem like what i had please e-mail me for the patch!!!