CorelDRAW X5 :: How To Set Envelope Function Box Size Prior To Entering Text Data

I am creating a template that will have four text boxes that I will populate from a merge document.  I need to have the envelope feature applied to each of the text boxes so any long text will be compressed to fit in the designated text box.

I understand the basic function, input text, select text, select Envelope feature but that sets the envelope box to the size of the inputted text, where I need a fixed text input box size.