OOPs,I didnt see that,It looks like they must use a 36V maximum switch then.
I just use a Wuxing horn switch to disconnect the motor .
http://www.ebay.co.uk/itm/321468618988?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Best chain for use with 6 to 8 gear rear is a Wipperman 7E8...