Needs halp with setting up server...

Posted these on FP:

Hello. I feel kind of stupid asking this, but does anyone here know how to add a web radio to a dedicated server. Often when I join a server I just have to type: "!radio" to open a webradio. Now, I've made a dedicated server, is there ANY way of adding a command similar to "!Radio"?

I appreciate all the help I'll get:)

Dan.

And:

Oddly enough half of my friends can't join my gmod dedicated server. About half of them can. Same goes for the general public. The rest get 'server not responding'
Any basic idea on how to solve this?

(I use port 27015)

EDIT: Regarding the radio, I've used this before: http://www.sourcetunes.com/index.php?page=11 - but then I downloaded a finished pre-compiled file from a place now removed...
Can anyone explain the 3-step installation instructions to me please?