Ipsec in Win2k ; how do i use it ??

we have configured VPN tunnel using 3DES on CISCO PIX 506 Firewall.through this IPSEC TUNNEL i can access the private IP of my peer. now when my leased Line goes down i can’t make use of this VPN tunnel. it doesn’t work on my backup leased line. atthis instance can i make use of IPSEC support built into Win2k. how do i configure IPSEC on Win2k Professional will it be possible to build a VPN tunnel through this IPSEC support in Win2k. if not whatz the use of IPSEC in Win2k ?