I'm hardly an expert but I've had the transmission fully opened and apart for all the seals two years ago and my brick is still running strong.
If by roller sleeve do you mean roller pin? (#5 in diagram---
http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51709&rnd=04302013)
There is a roll pin for each shifting fork, three total.
It takes a little bit of fussing but it does all go back together. I don't remember any special little moves or tricks that got it back together, just fussing and cussing, realizing I was soon to be awarded another mechanics merit badge for getting it all back together.
Also when refilling the transmission oil put in the measured amount (850 ml if I remember correctly) and then double check the level after a short spin.
I found I had to add nearly another 1/4 liter to get the correct level based on measuring the level through the filler hole. If the gears have been fully cleaned a surprising amount of oil is needed to get into all the nooks and crannies.
Good luck!