I'm not sure why the Visa Virtual didn't work, my understanding of it is that it works like a normal credit card for online transactions.
Did you get any error messages when you tried to use it?
If it you try again and it still won't work through our site, then there are some alternative places you could try.
For a limited time, you can get Dawn of Fantasy on IndieBundle.org
as part of the Get'em Greenlit Bundle (cheapest option)
Dawn of Fantasy is also available at: