Microsoft Windows [Version 6.0.6001] (C) Copyright 2006 Microsoft Corp. c:\windows>netsh ras aaaa set ipsecpolicy ?
set ipsecpolicy [psk=] ENABLED | DISABLED
[secret =]
Sets the IPsec policy for L2TP connection.
psk - Specifies whether a L2TP connection can use a Custom IPsec policy
ENABLED - Custom IPsec policy using pre-shared keys
DISABLED - Certificate Authority Policy.
secret - The pre-shared key to be used with custom IPsec policy.