How to put an external php function in VB's "scope"?

[StephenKay]

What I'm trying to do is this:

Call an external .php module with a click on a button, and somehow have access to variables declared in a plug-in (inside vB's scope).

In other words, a plug-in loads a template and fills it with some buttons, and assigns url links to the buttons. The buttons call a completely separate external php module like:

<a href="http://mydomain.com/forum/external_module.php?dothis=4>

So when the user clicks on a button, a php function in another file is called.

However, I can't seem to figure out how to have access to variables used in the scope of vB when I'm inside my external php code. Maybe this isn't possible...

Is there some specific include file I would need to include to make my external file "a part of" VB's world?