What is the actual part # of your machine ? There are at least 4 variations of same model. 2 are 1/3 phase 2 are just 3 phase. If yours is straight 3 phase your best to see if tech support will help you but I doubt it really because of liability but should still be your first try I think. Maybe they can give a hint if it is doable and if it is worth doing.
That manual covers 1 and 3 phase units as well as straight 3 phase I think.
SVI 300i cvcc
POWER SOURCE
P/N 34835 - 230 (208-230) / 460 (440) V ac, 1- or 3-phase, 50/60 Hz
P/N 34834 - 230 (208-230) / 460 (440) V ac, 1- or 3-phase, 50/60 Hz, w/ APS (refer to supplement F-15-204)
P/N 34872 - 575 V ac, 3-phase, 50/60 Hz (refer to supplement F-15-205)
P/N 34873 - 400 (380-415) V ac, 3-phase, 50/60 Hz (refer to supplement F-15-206)