[Building Sakai] port number

[Natalia Stash]

Dear Sakai developers, 

I am hiding the port number from the URL where our Sakai installation runs 
by setting ProxyPass & ProxyPassReverse in the Apache configuration. 
However when I log in and click on the courses tabs the Site URLs still contain the port number. 

In sakai.properties file I do not specify the port number as the part of the serverUrl. 
Could you, please, give a suggestion on how to solve this problem (so that the port number does not show up in the site urls)?

Thank you in advance, 
Natalia Stash.