Doors and Windows - Shower door glass

I have dismantled my framed glass shower for cleaning. To insert rubber gaskets into frame/glass connection is looking pretty difficult. Any technique that works? Any rubber lubricant that would help? Possible for it to be a one man job?

I've found that putting dish soap onto the gasket, smearing it all over the gasket with your fingers seems to helps a lot. And use a tool that won't cut the gasket as you push on it. They can be a real pain in the butt because they lose flexibility as they age. Kind of a pain to wash the glass afterwards but it's the only thing I've found that works. I've tried glass cleaner on the gasket, but it dries out too quick and isn't slick enough to help much.

JUST like XSleeper said.

For the tool that won't cut the gasket I have used either a screen roller (used to spline window screens) or a disposable plastic putty knife. (They're really dull!!) I'm sure there are other things that would work just as well.