http://www.feigao.com/sdp/85838/4/cp-102735.html
EDIT: Sorry you said 540
C
That drawing is still good for overall length screw hole location and shaft size/length. The 540C is bigger in diameter because of the cooling fins. IIRC its right around 40mm in diameter with the fins. I can measure later tonight when I get home if you want.
The 540C also has a small collar around where the shaft comes out of the motor. Its 1mm tall by 19mm diameter if IIRC. I can measure that too if you want.
That should at least get you going.