Adwords Cloaking Script

I need an adwords cloaking script. This is what I want the script to do: When I put up an ad on google, my display url will be DOMAIN 1. however destination url will be DOMAIN 2. When google adbot comes to check if the display domain matches the destination url, the script should redirect adwords bot to DOMAIN 1, so the adbot will think that display and destination matches; however, when normal users click on ad they will be taken to DOMAIN 2. Basically, the ad will say DOMAIN 1, the google adbot comes to check if it is in fact DOMAIN 1, and it should see that it is DOMAIN 1, but when other users come, they should be redirected to DOMAIN 2. They should NOT be redirected in iframe, but through other redirect script.