How do I loosen SLK320 serpentine belt tensioner?

[page62]

I've tried this over in the Tech Help forum, but nobody seems to have an answer. Yes, I'm cheating by asking about the C320, but it's the same as my SLK320...

My wife's 2001 C320 has a torn serpentine belt. Time to replace...now! I'd rather do it myself, but the tensioner has me puzzled. How do I loosen it in order to remove the belt. And when I retighten, what should I be doing?

Of course, what really puzzles me is how the belt got a longituditinal tear in the first place.

[page62]

Got the answer! Job is done -- here's the info, FYI:

How do I loosen C320 serpentine belt tensioner?