Well, I've been MOM for the last 4-5 years (altho you couldn't tell it from my picture) I should really put a new one up. I look SO young in that one. But anyway, i'm getting off track.
I'm 22 and I've been working with our choir/praise team for quite some time, and i had a similar problem once. And the way I corrected it was this. I simply said its my way, or the highway. The church board voted me in, and with that came a certain level of trust, and even power you might say. I run the worship service and what I say goes. I figure if the pastor doesn't like it, then He has to go to the church board and get the problem taken care of. So I simply said its my way, or the highway.
The choir member involved didn't like that so he ran to the pastor and the pastor didn't like it either. But, I told him the same thing. You helped put me into this position, and you have to trust my leadership and judgment just as I have to trust yours. End of story.
After that meeting, I have never had one moments trouble with the pastor OR with any other choir members. AND the particular choir member mentioned has accepted their place in the choir and is now doing rather well.
...its something to try.