What are you actually trying to do, Josh? Are you trying to set up a VPN connection? In OneCare, go to the advanced button on the firewall tab under Change Settings. On the ports and protocols tab, enable the IPSec Security Protocol and if you're looking to use VPN, scroll down to place a check mark next to the VPN entry. I don't know about IPSec filters, but I do know that there's no specific configuration of IPSec Filters in OneCare's firewall.
-steve