I was asked if I could program something for vBulletin. As I never programmed something for vBulletin I started to search for documentation and tutorials. Unfortunately I wasn't very lucky.
The most promising thing I found was this, but it looks like it was autogenerated and isn't very helpful for beginners. After some more searching I found a collection of tutorials in the vBulletin forums (3.5/3.6 Tutorial index), but the forum hides all code from non-members and I don't think I get an account without buying a vBulletin licence.
Is there a way to find if what I want to do is possible and more or less easy to integrate into vBulletin, without buying a licence?