Hi Igor,
One idea is you could remove most of the default mojoProfile settings, add a custom profile property as ISettingControl which must implement a simple get/set for a string but that string could be ignored and not really used for your purposes, then this is just a way to get a custom UserControl onto the my account page and inside your usercontrol you can have your own set of tabs and a separate save button that saves your data in your own tables.
Hope that helps,
Joe