I repaired mine with a thick nylon washer (more like a roller) that fits in the channel, and a screw with washers and bushing. All those things are available at a hardware store. The screw end inside the channel must be flat so it doesn't hang up. I admit it would have been easier to just order the part, but its an alternative.

__________________
1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma