Did you try to select both points and keep your pointer in line with the two points?
I assume that you have Dimension type set as true:
After that, I don't know of a way to change the orientation plane for the dimensions.
I know that reference sketch geometry (at the drawing level) won't work in a true view.
The only thing that I can think of is to place some reference stuff at the part level (planes, sketches, etc..., as needed) and dimension to that. However, getting it correct for your orientation might be a bit of a challenge.