Danny,
I suggest trying this on a remote client using 2k or XP:
Setup a PPTP vpn connection to SME.
Under advanced network properties for TCP/IP, set your WINS server to your MS WINS server if one is used. Set your DNS server to your Active Directory server if you have one. You also must set the "DNS suffix for this connection" and enter the domain for the AD domain controller. When you connect, your client will search wins, and dns.
If you don't define WINS and or DNS on each VPN client, it will use SME for both. This will work if your LAN clients use SME as dhcp server or each LAN client is has it's WINS server entry set to SME server IP Address. SME DNS will not allow you to resolve LAN clients when connected by vpn..(unless you have each client entered as a host name in server manager).
Hope that helps,
Ryan