close dialog box from program

[serpem]

I am writing a program that print Windows files in TIFF format by selecting MS Office Document Writer as the printer, then calling ShellExecute() to start printing. The problem is that the Office Document Writer pop a "Save As" Dialog box before printing each time.
Does anyone know how I can close that dialog from my program by either dismissing it or, better, activating the "Save As" button that's on the dialog?
thanks.