So, we just introduced a new little feature called the Coins Redirect URL. For some of the PayVault providers you send in some data into GetBuyCoinsInfo(), and get back a single url that your are supposed to show to the user somehow. This means a two-step process where you do the call in the first step, and display the urls in the last step if you want to avoid pupup-blockers.
The Coins Redirect URL allows you to bypass the method call, and just construct a url and show it to the user either in an IFrame or a Popup, and it will automatically redirect to the url that would have been returned from the method call, thereby making coin purchases a single-step process.
There's some documentation at the bottom of this page: http://playerio.com/documentation/payvault/coins
The currently supported providers are PayPal, SuperRewards, TrialPay and Gambit.
You can find Coins Redirect URL templates on the PayVault configuration page, in the section of each supported provider.
And finally, if you look up a user in the PayVault admin panel, you can find the same templates there, but with the correct userid filled in.