Considering the amount of code embedded into the PM code, it may get difficult to convert it to the Skin API and have it automaticly find it's themeing files. Of course, you'll have to take my word for it since you can't see the source.
I don't leave code half done, I merely extend it which eliminates the risk of me being lost in old code. Of course periodicly I may update old portions of code to newer standards but that's nothing big.