Last modified: 2014-07-15 23:54:38 UTC
As of now, authentication extensions not using Special:UserLogin cannot provide an acceptable interface through this function. It would be nice if there was some sort of hook to pass in an array of possible login forms (for those extensions that support more than one method of authentication) or at the very least override the link text to point elsewhere. I'd write a patch for this, but I have a feeling you folks are going to want to do it a certain way as doing this properly (supporting more than one login form, or at least the MW default along with another link) may be non-trivial and require additional translations. (Just speculation.) The function in question is in EditPage.php starting on line 1459 as per current SVN.
AFAICT, you can override login/logout links which are located in the personal URLs bar with the Hooks/PersonalUrls But there is no way to override the link generated by loginToUse(). Sadly, this function is responsible of the message (and the link) when a connexion is needed to view a page. (there _may_ be better hooks around Special:Userlogin and/or redirections for this kind of needs)