I have tried selecting/deselecting the individual parts, changing orientations, selecting "create opposite hand", etc... But haven't had any luck.
The parts themselves don't required opp-hand mirrored versions.
The gusset plates on the back-side are patterned.
Only the assembly and mates need to be mirrored and the pattern direction would need to be reversed..
I have attached some pictures.
Any advice on how to make it work?
For now I have just manually made a new "mirror" assembly as a configuration.