Whoops - forgot to ask - what version of InfoPath and what version of SharePoint are you using? Is your form filled out in InfoPath or in the browser? Thanks!
EDIT - also, I'm confused by this step: STEP 2 – open the form again and fill it with data from saved in the SharePoint list
Wouldn't the form already have the data in it? Can you give me a bit more direction about your design? Or attach your form template?