XML import into Form on open

Hi there,
I created a form with Life Cycle Desiger which ist linked to a xml datasource. When I use the Preview in Live Cycle Designer the Form fields are filled with the content of the XML File. When I open this file in Acrobat the form fields are empty. I can create a button with a java script on click that imports the values of the XML file in Live Cycle Desiger but I found no way to execute this script when I open the file.
Any ideas?

Thanks in advance

Arnold