Hi,
I've just checked your website and as my colleague pointed out, you need to "purge" the already generated SEF URLs in JoomSEF. You can either use the buttons from JoomSEF's Control Panel on the Maintenance tab, or JoomSEF's URLs Manager page to do this.
After deleting the already created SEF URLs they were regenerated according to your current settings.
For more information please read the How It Works and Working with URLs chapters of JoomSEF's documentation:
www.artio.net/joomsef/documentation