Its easy
go to the suppport site
and go to via folder and download the .arp file for windows and mac to your computer
Then on the controller go to advnaced services -->vpn services --->via
And the .arb files upload them using the browse button i show you an image.
In the file that Collin gave you, you will get indeep detail of this
You willl even get a custumize welcome html code which you can upload
With that you will have something like this:
Cheers
Carlos