Save credentials on phone

Hello, I'm using a custom login page on my app that validates the user via soap calls witch doesn't use the default Mendix users. I'm trying to find a way to save the users credentials so that you don't have to login every time you open the app. But i have no idea how to accomplish this, any ideas ? This only has to be possible when logging in with a phone.     
1 answers

You can enable it with Phonegap package build,