Do you use the webserver or the appserver?
For the webserver: (assuming default paths)
You probably can do this by editing:
/opt/SUNWwbsvr/https-YOURSERVER/config/server.xml
Try to add something along the following:
<WEBAPP uri="/" path="/var/opt/SUNWps/https-YOURSERVER/portal/web-apps" enabled="true"/>
For the appserver it is probably something similiar, please let me know if it works!