Backup on DAV

[Gaute Amundsen]

Hi

First, thanks for the webdav support :)
eldav was getting very dated.
I suspect you may have a small influx of Zope developers like me once
word gets around.

However there are a few snags.

There is some footwork involving content-types that eldav handled, but
tramp / gvfs apparently don't.
The effect is that when emacs creates a new file after renaming the old
one for backup, it gets created in zope as
"text/x-unknown-content-type".
( in my test case I presume it should be "text/pythonscript" or somthing
to that effect, but I haven't fired up wireshark to look just yet )

setting make-backup-files to nil solves that, but then all backups are
disabled..

Is there a way to disable backups only when in tramp, or even better
only when using dav?

I've fooled around with tramp-backup-directory-alist and
backup-by-copying quite a bit, just to make the backup fail quietly
somewhere out of the way, but all I ever get is: 
"Cannot write backup file; backing up in /home/gaute/%backup%~"

currently I have
(custom-set-variables
'(tramp-backup-directory-alist (quote (("." . "/emacs_backups/"))))
...
)
where /emacs_backups/ exists in zope

And I tried:
(setq tramp-backup-directory-alist  (cons (cons "."
",~/.emacs.d/backups/") ()))
where I got some complaint about not being able to expand ~

I understand something like this should be possible if I could only get
the path to work...
(cons "/dav:." ",~/.emacs.d/backups/")

Regards

Gaute Amundsen