Microsoft ActiveSync Ports

I use Microsoft ActiveSync to sync Outlook Xp (2002) to Windows Mobile 5 in my Palm Treo phone. Contacts sync perfectly but the Calander fails. Forums on the net suggest that the error code may be caused by a port problem.

ActiveSync requires 6 specific ports that cannot be filtered. I am unclear as how to ensure that these ports are not being filtered in the COMODO firewall. Are the ports unfiltered when I set up a Port Set that contains them or is there another step I should be taking? Does something have to be done in the Network Security Policy which I know little about? Any help would be appreciated.