I found the information below on a different forum. There's no guarantee that it will work, but it's deifinitely worth trying.
1st: go to your firewall settings
2nd: under the exceptions click the 'Add port'
3rd: copy this phrase C:\Program Files\Ascaron Entertainment\Sacred\Sacred.exe to the 'Name'
4th: as for the port number put 2006 and then select ok
5th: then when done u go back to the new port that u created and select 'Edit'
6th: select the 'Change Scope' and go select the custom list type in you and your whichever frens that u wan to play with them on lan ip address on it and den select ok!.. 7th: aft all those steps plz run ur dedicated gameserver in ur sacred folder and put the TCP port to 2006 and select lan game and select the IP which is the same and shown on ur HAMACHI network on the TOP, the IP is big and can be seen when u connect ur hamachi (plz refer below on how to download hamachi)
If the above does not work, try referring to this post:
http://forum.sacred2.com/showthread.php?t=46093