Mirroring against a point and a line seems working in the trunk version (I think it need some testing but the feeling is right here). Also the repeat line pattern.
How it work?
- Pick your shape first
- Pick the point (for Mirror Point) or line (for Mirror Line or Repeat Pattern)
In case of Repeat Pattern you are asked how many times to make a complete (360 degrees, 2*PI) rotations and in how many steps should translate the length of the whole line.
See screenshot for Repeat Pattern of one of the initial rectangles, 1 complete turn and 10 steps. If you simply want translated along with a line (to make stairs without rotation) you will need to put 0 (zero) for complete turns when the dialog will appear.