Hi,

I ran into a similar situation which we resolved by using conditional formatting.

We created an additional field in our form's data source, but did not create a control for it on the form - preventing the user from filling it in manually.  On the click event of the button, we set this field's value (in this case, the current date and time) through code (a rule would also work).  We then set up conditional formatting on the button so that if this field contained a value, to disable the button.