proxying to apache/svn, COPY fails, but without HTTPS

[Samuel Vogel]

Hey guys,

We proxy http://svn.domain.com:80 to http://localhost:81, where an 
apache server with mod_dav_svn is listening, which is binding only to 
127.0.0.1:81.
We do get a "502 Bad Gateway" for COPY requests. This topic came up a 
couple of times on the list, but issues with HTTPS vs. HTTP always 
caused the problems.
This is however not the case with out setup, the SVN client uses HTTP 
and we proxy to the backend via HTTP.

Our nginx config:
server {
     listen   80;
     server_name svn.domain.com;

     location / {
         proxy_pass http://localhost:81;
     }
}

Apache config:
Listen 127.0.0.1:81

     ServerName svn.domain.com
     UseCanonicalName On

<Location />
         DAV svn
         SVNParentPath "/var/lib/svn"
</Location>

Any hints how this could be solved?

Regards,
Samy