I think you may have done this, but just in case
Check what settings you have in the "Alarms" section of the system setup
- Press "Menu" twice
- Highlight "System Setup" and pres enter
- Select "Alarms"
You should now see a list of all the categories of airspace and whether they are set to alert you or not.
If that doesn't work, let me know and when I'm in my machine this weekend I'll take a look. I'm better at working this stuff out when the unit is in front of me.
Joel