The features of online backup is an online service, you can't typically just "crack" that. You'd have to reverse engineer the protocol and put a server in between that you control.

I can see this app you mentioned on mobilism.org. You need an account to get to the forum though, and I don't know if they're open to signups.

Aren't just about all emulators open source? I bet you can find everything you need for free on F-Droid.