Ive never used pro to develop (even though I have access to A6 Pro from a previos job) but maybe you could try the A6 ones to get an idea on how to effect it (maybe download A6 and use your key to activate it).
There are rules about orientation and using none-flags for non mirrored surfaces on the same block which could also apply here as well.

Then again, you could try to contact users who have successfully employed it like Dan_Silverman and George Pirvue (only ones I am aware of who usesd the mirror systems from Pro versions)