Seems like you need to fork the ldap login handler into you own login handler to be able to do that. Since the ldap login handler authorizes the user against the eZ Publish user after you login (on each request after user is logged in).
I have solved the problem by hacking the ezldapuser.
I was "on the search" for a cleaner solution.
Any way, can any one explain to me how to do a clean "fork" for this, like creating my own auth method like an extension and activate it like the ldap one?
[UserSettings]
ExtensionDirectory[]=<extension_name>
#used login handlers, comment out standard if you don't want it as fall back
LoginHandler[]
LoginHandler[]=<login_handler_name>
LoginHandler[]=standard
Then you activate the extension, in admin or in settings/override/site.ini* (Might want to place the login handler specific ldap.ini settings inside the extension settings folder also!)