SMS notification on WM6

[Guest gfwk2]

I have the HTC Touch and as per my power save settings, it goes to sleep after 2 minutes of inactivity. However, when I receive an SMS, the phone wakes up and a notification icon appears ... but the phone never goes back to sleep. This is annoying because if a message arrives when I'm in bed, I wake up in the morning to find the battery almost completely drained.

Is this a WM6 thing or just specific to the HTC Touch? Can anyone have a solution (I tried disabling the notification by tweaking the registry but then it never notifies ...)