In Reply to Christopher Thompson:
I feel your pain. I'm a contractor as well and have to work within the constraints of whatever company I'm with at the time. Having the master assembly as a Step file would bea royal pain, but you probably can't do much about that.
When you create a CSYS, you have the ability to both offset and rotate it at the same time. In WF4 when you create the csys, the dialog box that comes up has 3 tabs on it, one for offset (called origin), one for rotation (called orientation), and one for properties. When you use the rotation things get even more cumbersome than with just offset. These angles are relative to yourOLD csys, not the new one, even though it shows the angles on the new csys location. It's kinda confusing.
Good luck.--Jeff Sampson Engineering-----