Coordinate Systems on Workbench (Mechanical)

[rcfanatic]

Is there no way to define a coordinate system without having it defined by the global axes, or a part of the model geometry? I'm trying to model gravity at 45 degrees to the global coordinate system, and I have no model geometry that will express this.

On other parts if you choose to define by geometry it will compute the directional unit vectors for each axis. Why won't it let you input these yourself w/o choosing geometry? Please tell me I'm overlooking something!

Thanks!
Adam