Wifi-Ipsec passthru--smoothwall--LAN

[mboy]

Here is my Plan. I bought the Dlink 614 (will pass Ipsec). Going to use it as a wireless router---into a an old box running smoothwall. Planning on disabling SSID broadcasts, enabling MAC filtering and then only allowing IPsec traffic to pass thru the wireless (ending at the smoothwall box). AFter that I will be allowing traffic into my LAN and out to the WAN. This should theoretically give me tons of security as it will be next to impossible to connect to my AP and VPN into the smoothwall box, encrypting all Wifi traffic. (this will only be used by 6 people at most within my organization).
Any suggestions, thoughts about this plan. Anyone with experience with a windows based 3DES VPN tunnel to a smoothwall box?
Thanks.