Showing full page before with “Save As Dialog”

I built a downloading piece that works fine. Here’s how it goes:

1 – User chooses a format to download
2 – The next script sets up the file to download
3- The “Save File As” dialog is shown

This process works fine. But I want the “next script” to display a typical page saying “Your download will begin in a moment. If it doesn’t start click here..”. But I can’t get the page to display itself before the “Save As Dialog” comes up..

Any ideas??