Hi !
I think the manuals for RBMs Towerhawk and Onboard (ZorroII-expansion) are available on RBMs site
http://www.rbm.de .The site might contain some German,but the manuals atleast were there,at some point,
in English also.The power supply indeed plugs into the Keyboard interface and it plugs to the A1200 via
a small adaptor from the outside of the tower. The 20 pin plug is the one coming from the ATX supply -
I don't know the 'pinouts' of it or whether it's a standard or made specifically for this tower (no
experience in power supplys..). The two 6-pin plugs,labelled P8 and P9 respectively,come from the
OnBoard ZII-addon.Also,On the interface there's the obvious keyboard flexcabel connector and on it's
left side the towers LED connectors and the leftmost connector is for the A1200 LEDs.
Unfortunately,you won't find the 'pinouts' of the power supply 20-pin plug from the manuals and unfortu-
nately I'm too lazy to open it up

(and probably I wouldn't be able to help anyway,since I don't
have the expertise).
Regards,
Kenneth