See the PHP files provided in deploy folder of the source code.
These subjects might interest you too:
http://www.sweethome3d.com/support/foru ... hread,1113
http://www.sweethome3d.com/support/foru ... hread,1454
http://www.sweethome3d.com/support/foru ... 2608#11820

About Web portal, I have no idea.