It's a challenging concept and I will do my best to help you to improve your software. I have an IT degree and I am quite an expert, so email me your problem and we will find together the perfect solution.
I purchased the ITB w/o registering an account here. It allowed the purchase, I went to download it, and it then said I wasn't authorized to download, I had to sign in first. I didn't have an account to sign in to.
Possibly, you may want to add that to your purchase page, like "You must have a registered account with us before making a purchase". Just sayin' :)