I don't have much experience designing forms in Outlook 2003 and I need to
customise an existing (customised) form. This shouldn't be difficult, but I
can't find what I'm looking for...

Basically, I have a text field that stores numeric data and a checkbox. The
default value in the text field is '0'. When this value is other than '0', I
want the checkbox to become checked.

Where do I go to configure this event-based rule? I'm looking at the
properties of the controls in question and not finding the means to do this
simple task.