Well, plus 1 for actually having the main manual and for using it.
Makes for a powerful lesson -don't over tighten the dam thing.
Don't sweat it too much, every mechanic has done this as well.
Did your break off one or more of the three mounting screws?
Fiche says these are 6mm x 20mm, 6mm x 25mm, and 6mm x 50mm
Flange head screws /bolts ...
1) Try to remove the stub of the remaining bolt -if any- using vice grips
2) If no stub is left to grab, then you need to drill out that little b~tch
--take off the final drive cover, being careful not to break anything else :^)
--take a small size drill bit, say about 1/8th inch
--carefully drill into the stub of the bolt and try to keep the bit centered
--drill in about 1/2 inch
--tap into this hole the extractor tool
--then use a wrench and back out the broken bolt
Sometimes the screw just strips the threads out of the case ... (swearing ensures)
If that happens you need to install a thread repair kit.
This might help orient you on the process ...
http://www.wikihow.com/Use-a-Screw-Extractor