I had this same problem where the radio mutes for a few seconds when a message appears on the screen saying Battery Full etc.... This is how I got round it, this is for a recent series 60 device, eg. N80, E65. For a Series 40, you'll need to figure that out yourself.
1. Create a new Profile, called "Car Kit"
2. Personalize that profile by setting "Key Pad Tones" and "Warning Tones" to off
3. Settings -> Enhancements -> Car Kit, set the default profile to "Car Kit" or whatever you called it in Step 1.
It should now stop muting the radio when you press a key on the phone or when a message appears. It should also automatically select the "Car Kit" profile when you put your phone in the cradle or connect via bluetooth to the car kit.
If you want you could also enable "lights" under the Enhancements menu to keep the display on and also "Say Callers Name" under the "Car Kit" profile. Doing it this way, means it will only do this for the "Car Kit" profile.
K.
Message Edited by kraven on 23-Jul-200703:01 PM