GMod 13 Server Problem

Hi,
I’m trying to host a server on the GMod 13 beta for me and my friends, I used HLDS update tool and followed the tut until I had all the files, I have also port forwarded the ports from http://maurits.tv/data/garrysmod/wiki/wiki.garrysmod.com/indexb076.html.
I can join my server, but when I invite friends they say the server isn’t responding.
When I tried to find my server on the list, i couldn’t find it however it does appear on the local network list.
H have tried using sv_lan 0 and heartbeat but to no avail.

Help anyone?

(( I did not realise there is a seperate discussion for GMod 13 so i reposted this on the GMod 13 Discussion ))