Okay, I'm really not sure why anyone has not tried this before, but I've successfully removed the cap from a fog light myself.

There are just a few Torx screws that you have to remove to get the whole assembly out. Once you have the fog light removed, you will see two sections that you have to separate (little clips). There's also a screw that when you loosen, will allow you to pull the assembly apart into two halves. Then you're free to take the bulb cap off.

The biggest speed bump I encountered was trying to get the assembly back together, because the rubber o-ring was a little difficult to get seated properly.