I can't flip asymmetrical parts from mods

[Sir Keksalot]

So I noticed that, for whatever reason, Blitz's wolverine claws are upside-down. At least, I think they are. The fourth, shorter blade is oriented beneath his hand instead of by his thumb when placed on his arms, and I can't tell why. So I figured I'd make each individual claw asymmetrical so I could flip them and make them look normal. Only...ctrl+F did absolutely nothing. I figured something was wrong, but eventually I realized that the flip function only works on vanilla Spore parts. None of my modded parts can flip. Why? Is there a fix for this, or should this go under feedback?