But did you see that there are two examples of page.inc?
One is named page.inc_SPLASHFORM, and works as normal phplib: the form is splashed on a page by itself. This is a global beahvior.
The other one is named page.inc_DEFERFORM, and the showup of the form is deferred for later use.
You have to use this one. An example is in the showoff.php3_DEFERFORM.
Did you read the README?
Gian