Mounting a SharePoint site in Ubuntu 14.04

Question

I am trying to mount a SharePoint drive in Ubuntu 14.04, and utterly failing. It's an external site which uses a username that includes an @, and obviously a password.

First, I have tried to use Nautilus from Gnome as suggested here. With or without the username, it fails with 403 FORBIDDEN.

This answer suggested Konqueror. This one gets stuck This is probably due to the fact that the rest of the system is Gnome, but still.

I have also tried to mount, using davfs2, the external drive. It requests the username, but then when the password is issued, again the same error, 403 FORBIDDEN.

Finally, I have used cadaver, as suggested elsewhere. Before even asking the password, it returns 403 FORBIDDEN.

Is it simply impossible to use 12.04 (and version of Gnome) for that? Should I uses something else entirely?