Shalom JewishDude,
I don't do the Friday worship, but I work at an Islamic centre from time to time. I do not disclose my belief, and have been getting along with them fine. They're very friendly, outgoing and kind-hearted people, and I do feel a strong sense of family there (everyone taking care of each other).
As long as you don't confront people regarding their belief systems, you should be fine. People will reach defensively if their belief is attacked/criticised (cause it is part of their identity). My experience is that as you get to know other muslims (the traditional ones) and progress with your friendship, you'll slowly open up in a non-confrontational way and chances are they'll respect you for who you are, as long as you remain nice and friendly. The case will be different if you declare out loud that you don't believe in their practice and engage in arguments to prove them wrong - that's just asking for fire.
So yeah. In my early stage, I did get into lots of sour arguments with the traditionalists 'cause I was too insecure with my own belief, and tried to prove them wrong. But now, I find that people will accept and respect your beliefs, as long as you don't try to invade their spiritual space.
That being said, the people at the Islamic centre that I attend are extremely nice and have been treating me well ^_^. Shalom.
