[vbSuperfan]

I'm quite surprised that I cannot find anything on this topic on Google, since it seems like an extremely likely thing for people to want to do, that is: Creating a special BBcode that can execute some certain PHP code of mine and then produce some string based on it?

In my case, I simply want the BBcode to return the user ID of the vBulletin user currently viewing the post where this BB code is located, like this:

Your User ID is: 1234

Does anyone have any tips for good skeleton code, tutorials or other useful starting points for creating your own PHP-based BBcodes like this, by means of an extension/product? The official vBulletin support indicates to me that this should at least be possible, here?

I've even heard that this (PHP-based custom BB codes) was standard functionality in vB4, available directly from the AdminCP, but removed in vB5, which makes it even more likely that a lot of people would have liked to created such extensions/products for vB5, so what am I missing?