Here is what I did to get something similar to work.
First I created a hostname in the server manager.
docushare.mydomain.com IP 10.x.x.2
server1.mydomain.com IP 10.x.x.3
server2.mydomain.com IP 10.x.x.4
I then created a template in "/etc/e-smith/templates-custom/etc/httpd/conf/httpd.conf" called “93ProxyPassServer”.
I added the following lines to 93ProxyPassServer to connect to my NT Server running Tomcat webapp via the SME and SSL.
ServerName docushare.mydomain.com
ProxyPass / http://docushare.mydomain.com:8080/
ProxyPassReverse / http://docushare.mydomain.com:8080/
NOTE: I did not try to go to a "/portal" directory like you are. I access it as the root of my website.
Most of my sites run http so the entries look like this:
ServerName server1.mydomain.com
ProxyPass / http://server1.mydomain.com/
ServerName server2.mydomain.com
ProxyPass / http://server2.mydomain.com/
ServerName myserver.mydomain.com
ProxyPass / http://myserver.mydomain.com:8080/
ProxyPassReverse / http://myserver.mydomain.com:8080/
If found if I put the server hostname in the SME hosts Panel, I did not have to use the ProxyPassReverse statement unless I am going to a non-standard web port.
Tony P.