Reber wrote on Feb 22^nd, 2012 at 5:08pm:

I can't target any of the ships with all other AS-missiles I tried out also in other locations. I'can't target any groundtargets what so ever. The target mode takes me to other airports. I should be able to target buildings and other targets on the ground wich I choose not the system. Toni

Have you set it to Air to Ground? I can fire missiles at AI aircraft parked at airports as well as the Tanker Trucks and a few other vehicles (all at the airports).
At the moment, Weapon for FSX does not have the capability to target or destroy buildings. I am hoping that these features, and the capability to drop bombs, will become available in a future update.

Mark