I have Tomcat running on port 18080 and Apache on port 80 with the mod_jk plugin forwarding requests from the /confluence URL on port 80 to Tomcat. When using the username tag it renderes with the internal Tomcat URL, like "http://metro2.corp.telenor.no:18080/confluence/confluence/display/~t535293 istead" of "http://metro2.corp.telenor.no/confluence/display/~t535293". It also doubles the contextpath.

The server base path is: http://metro2.corp.telenor.no/confluence