Probably the easiest thing to do is to share with you the .user file I wrote to allow for this. You can find it
here. It allows for a "Naked" Extra. Just add your Extras and Flaws on it and then adjust their "Partial" ranks to match what you're adding it to. Adding Removeable by itself doesn't help much (because it applies it against the "Variable Descriptor" part), but you can add that power to a Device.
Let me know if I can help you in any way with it.