Reverse proxy

Up to recent, I had my blog at my university webspace, ie at a URL like

http://myuni.ac.at/mydir/blog/

Shortly, I’ve had a domain like

http://mydomain.at/

set up to redirect to

http://myuni.ac.at/mydir/

via a reverse proxy; that means, I can now reach my blog via

http://mydomain.at/blog/

In order to completely hide the “ugly” http://myuni.ac.at/mydir/blog/ URLs also from subsequent links from the blog start page, I’ve adapted the permalinks, and tried to also set the siteurl and home wp-options to http://mydomain.at/blog/.

Unfortunately, when then trying to access http://mydomain.at/blog/ , I’m redirected to http://mydomain.at/mydir/blog/ ( with mydir as of http://myuni.ac.at/mydir/ ) which of course doesn’t exist. (I’ve also tried to leave siteurl set to http://myuni.ac.at/mydir/blog/ and only change home, but to no avail).

It’s apparently wp-login.php that causes the redirection. I don’t have much of a clue about the WordPress code, but I figure it might have something to do with the redirect_to server variable. Can this be cured in a way that enables me to transparently use WordPress with a reverse proxy that caches a directory on a different server?

Any help appreciated.
-BR