Sorry, I can't answer your major question. The answer to your secondary question is Scipio, at the battle of Zama (the Carthiginian was, of course, Hannibal).
the ist series does not support mirror lock up.
the reason for mirror lockup is to let the cam settle down it's movements before aperture release. the continous mirror lockup is for CLEANING only. you can however choose the F button , go up with the four way controler and choose the 2 second option. this will lockup the mirror for 2 seconds before the shutter release.