Reverse Proxy to BI Publisher - won't work past logon

Hi.  I need to reverse proxy to BI publisher.  In doing so currently it brings up the logon page successfully - using the reverse proxy URL.  However, after entering username and password, it loads BI publisher into the browser using the URL of the actual server housing it - bypassing the entire Reverse Proxy process.  Does anybody know a way to solve this?
Note: the reverse proxy is setup to work properly because it can success fully reverse proxy to OAAM ARM admin console on the same box, in the same manner, except in that case, it continues to reverse proxy after the creds are entered - as it should.