I did my own Gen I. I have not been in my Gen II's case. I will have a look at my FSMs tonight and see if I can help at all.

In the mean time, do you know about the how the main shaft's gear (forget it's exat name, too) might not fit through the hole in the case? In which case you will need to assemble the gear/shaft in the case. And in order to get the last snap ring on after that is all said and done, you will need a ground down snap ring pliers.

Here's my thread from last year...

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com