If the mobile device is an iPad or iPhone, user must type in the mobile url with domain, userName and password details ONCE.
When access has been gained, you can then bookmark it - but instead of the bookmark option, you can choose to add a desktop icon. Which is neat because it protects the username and password from prying eyes.
I'm told Samsungs have a similar option but as I've never used one, I wouldn't now how to do it.