The good news:  In a component pattern, you can choose different configurations of any specific instance than the seed (since 2012 or earlier - not sure how long we've been able to do this).

The bad news:  It seems that in a mirror pattern, the location of the mirrored instance is based on something that doesn't seem intuitive to me, as evidenced by the fact that if the seed component has a hole in it and that hole is suppressed in the configuation the patterned instance references, the instance isn't aligned with the seed.  Am I missing something, or is this a bug? 

I'm attaching an example created in 2012 sp5ev, but I get the same behavior in 2013 sp0.

Charley Leonard