BB Curve 8500 :: Instant Messenger Tones

Ive had it less than a week and im getting more familiar with its features and how it operates, however, ive set up the BB instant messenger using PIN.

Now, the main problem is the sound notifications for the messenger.

In "BlackBerry Messenger Alert" I set "out of holster" to 'tone' and the volume to 'medium'. And, in:

"BlackBerry Messenger New Message" - The same.

When i recieve the INITIAL chat request, my phone makes the sound ive set. Once in the messenger chatting i still get the notification sounds.

I have tried all manner of different setting from muting, and setting 'tone' to 'none'; both in holster and out of holster.

Basically, i want my phone to notify me of the initial/new message, but NOT beep/sound during the actual conversation.