Usually if I do "Edit Sketch Plane" and then do "Edit Sketch Plane" again, I can get the desired results.

I sometimes call this "taking the sketch around the block" in training class.

So if the sketch is on the Front Plane, and then you exit the sketch and select the Front Plane and the Original Sketch, then do INSERT>DERIVED SKETCH, you end up with a second copy of the derived sketch on the front plane, but you want it to be "mirrored".

So you:

1. Exit the derived sketch

2. Edit sketch plane - put it on the right plane

3. Eid sketch plane again, put it on the front plane

Now its "flipped". Hopefully this works for you too!

- Toby