Mariano Gomez follows up his previous posts with a look at using pass-through sanScript in VBA to return a file path to a Dynamics GP modified field form.
Mariano continues some nice dev posts with lots of screen shots and code.
Using sanScript in VBA to Return a File Path in a Modified Form
Archived post from 2008. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.