'93 Honda Power Window

Hi. On a '93 Honda Accord EX station wagon, I just replaced the jammed
& broken regulator & motor assembly on the drivers side rear power
window...BUT it's very slow going up & there was a loud "clunk"
dropping a black plastic "U" shaped part to the bottom. Cleaning &
greasing the channel with dielectric grease has helped, but the window
clearly has a mind of its own on side-to-side alignment on being
raised. The other rear window stays positioned against the rear channel
going all the way up, so I'm guessing that it's an alignment part to
hold it against the rear channel. It doesn't appear to be broken, but
does anyone have any idea where the heck does it go? ...or where a door
schematic might be found? Otherwise I'm going to have to tear into the
other rear door to try to spot its location.

Here's a .jpg of the part:
http://img.photobucket.com/albums/v628/Farsworth/HondaWindowPart.jpg
Thanks!