Racoon (IPsec) and Windows 7 VPN

I'm trying to create a VPN server on my Linux From Scratch server using IPsec and L2TP. I would like to log-in using only a password, not using certificates.

I'm trying to make this work using ipsec-tools-0.8.0, xl2tpd-1.2.8 and ppp-2.4.5. I want to log in using Windows clients.

My racoon.conf

path pre_shared_key "/usr/local/etc/racoon/psk.txt";
remote anonymous {
        exchange_mode main,aggressive;
        doi ipsec_doi;
        situation identity_only;
        nonce_size 16;
        initial_contact on;
        passive off;
        proposal_check obey;
        proposal {
                encryption_algorithm 3des;
                hash_algorithm sha1;
                authentication_method pre_shared_key;
                dh_group 2;
        }
}
sainfo anonymous {
        encryption_algorithm aes, 3des;
        authentication_algorithm hmac_sha1, hmac_md5;
        compression_algorithm deflate;
}
Almost independent of how you configure racoon, if you create a default VPN-connection under Windows 7, you'll find out that it will not work and that the log file ends with:

2011-04-23 11:41:49: ERROR: no suitable proposal found.
2011-04-23 11:41:49: [192.168.0.3] ERROR: failed to get valid proposal.
2011-04-23 11:41:49: [192.168.0.3] ERROR: failed to process ph1 packet (side: 1, status: 1).

Apparently, the VPN client of Windows 7 uses certificates by default. So if you want to use pre-shared keys for authentication for L2TP under Windows, you have to change this explicitly in the properties of your VPN client. (Under Security -> Advanced Settings -> L2TP -> Use preshared key for authentication) (which should, of course, be the same as the key that you have set in (/usr/local/)/etc/racoon/psk.txt.)