He means on your personal download page, in the address bar you'll see something like:

"http://sales.limewire.com/040345/RTdfhTRYghdfgGFHJgferDFGdf/"

All you have to do is add the word "beta" at the end of that URL so you'll have:

"http://sales.limewire.com/040345/RTdfhTRYghdfgGFHJgferDFGdf/beta"

That is not a real link though, you'll have to do that in you're own personal download page.