DSC 832 Sync Problem

I had to replace a wireless window contact with a new a 900MHz WLS907. The question is: How do I sync it with the LED Key Pad? The issue that I'm having is that every other day the key pad sounds as if someone has opened a door or window but there's no trouble light indicating a problem. On two occasions I set the alarm and when I got home the memory on the key pad was lit. When I press the code to see where the breach was it indicates that it was at the window where the new WLS907 was installed, but the window was not opened! I'm guessing it's a sync problem. New batteries were installed by the way and a new magnet as well. Any ideas or recommendations.

DSC 832 Sync Problem