The x50 and any roofing interaction should be minimal. The wire antenna is high enough away from the roofing, that should not be an issue, either.
Now, for your question. You have many optinons for your antenna supports. A local club station has a rooftop tower mounted on a metal roof which has been secured to the steel framing under the roof. It works just fine.
A few years ago in QST, there was an article about a rotor/tripod mounted in the attic and just the mast coming out of the roofline. You may be able to do this without having the rotor(vert doesnt need one) and having just the mast exposed above the roofline. I dont know which QST, but a members only search on arrl.org should help you find it.
Another option is to use a push up mast secured to the side of the house. Or just 3 - 10' 1 1/2" masts secured to the house.
There are several inexpensive ways to do it. Do you have a desired height?