fyi - Advance sales for the ZBF glass and beer tokens is open and it appears this year they allow for buying in advance via multiple methods (including PayPal) and picking up at the venue.
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http://www.zbf.be/index.php?lang=UK&page=4
In previous years, the advance sales did not work well for those of us in the USA. I can't say how well this will work, but I do know (from experience), that there can be a long line to buy when you get there...
I'm planning to try this out--will see how it goes.