The mempak works for me with this plug in. I had to configure it first. The default configuration it came with didn't point to a real location on the hard drive. Once configured, mempak worked fine.
Created a folder to hold mempaks. Then in the mempak screen configured it to look for that folder. Used it to create mempak and it worked fine in the games. I've created several mempak files and you can pick which one you want to use (and if you name the file a name of the game that's on it, it's easy to figure out which one to use).
In fact, where different games prompt you to insert mempak and then rumble pak, you can use both. Just go to configure input plug in and change to the one you want and save.
Great plug in.