What do you mean?
You want to make a cracked client like AnjoCaido? (Where you're able to log in to cracked servers, etc)?
Someone a few weeks ago created his own Minecraft launcher (a premium launcher) and customized it for MPGH, so I know it's possible. You may have to ask him. Here's the thread link:
https://www.mpgh.net/forum/335-minecr...-launcher.html