2003 Ford F150, Securing Rolltop Tonneau

Hello, folks,

I have just had installed a Clifford Matrix RSX3.5 Remote Start security system in my 2003 Ford F150 Super Crew truck. The system is great; however, I am having problems trying to secure the truck bed/cargo area. Currently installed on the bed is a rolltop tonneau cover like this one:

http://www.rollnlock.com/Pages/Products.html

Now, originally the installer placed a Directed Electronics 508D Field Disturbance Sensor, mounted on the front right side of the bed. Unfortunately, due to the nature of the rolltop cover (which is inherently flexible), the system will constantly warn away, and sometimes alarm, especially on windy days. It will go off if you look at it sideways, and even set at minimum sesitivity, it still activates the system. As I said, the problem is in the cover, which flexes, thus casing a 'field disturbance' even in the slightest breeze.

The installer originally wanted to install a basic pin switch, but once again, that damn cover doesn't have any kind of provision for mounting this kind of switch setup.

Questions:

1) Is there any sort of 'directional' motion detector available that could be 'aimed' downward toward the bed surface area (away from that damn cover) so as to not be affected by the fluctuation of the cover? 

2) Does anyone know of any other kind of contact switch that could be set to trigger if the cover is opened? I was thinking perhaps of something similar to the magnetic on-off switches that are used on doors and windows in residential security applications - anything like that available for automotive applications?

3) Could you point me to any supply houses that might stock a wide variety of door/pin/security switches for automotive applications? I'm sure I could  fabricate something; perhaps I could get some ideas by browsing a large selection of security switches and the such.

Thanks in advance for any information and assistance.

Hello, Jeff,

That is the solution I have been leaning toward, but I just thought I'd put it out there for suggestions.

Thanks again.