So it sounds like you are referring to the gnome keyring pop up message window. If that is the case (and I have a different setup than you do so I am not completely sure) then you can in fact just set the user and password to empty. I am not sure if that will stop the pop up appearing but I imagine you can then just skip over it. I have the same issue with a vpn and the following link has a solution to removing the pop up from reappearing if you have already set a password.
I guess you could also try removing the gnome-keyring (if that is what it is called) package but sometimes that can be difficult due to dependencies.
hth