Block all websites apart from the homepage for all users. Citrix environment with Server 2003.

Citrix Xenapp 5 and Windows server 2003 environment. We want to force Firefox to kiosk mode with a pre-set homepage for all users. I also want to lock this to only one website. I have managed to set up the kiosk mode with R-Kiosk addon and Mozilla.cfg file. I am trying to use BlockSites to block all internet sites and only allow the one site with the whitelist option. I can get the addon to install for all users, but can’t get the default settings across. I have tried to add this with the Mozilla.cfg file, but it looks like this addon is getting it’s settings from the profile folder. If I set the preferences for the addon in Mozilla,cfg file, it actually picks it up but it doesn’t apply it to the addon for some reason. Does anyone have any other ideas on how I can lock this down to the one site?