No problem here using 2010. It probably is not as intuitive as it could be but that's AutoDesk for you. I got it to work the first time out on both a box and a cylinder.
My inputs for the cylinder shown below.
(TRIM mode) Current chamfer Length = 0.2500, Angle = 45
Select first line or [Undo/Polyline/Distance/Angle/Trim/mEthod/Multiple]:
Base surface selection...
Enter surface selection option [Next/OK (current)] <OK>:
Specify base surface chamfer distance <0.2500>:
Specify other surface chamfer distance <0.2500>:
Select an edge or [Loop]: Select an edge or [Loop]: