submit data ->preview page ->back to data enrty

[eluser]newuser2[/eluser]
I'm trying to implement a form, that once successfully edited, goes to a preview page. The only problem I am having is reloading data back into the 'add content' page if the user decides to not submit the form in the preview page.

All inputs have the,

Code:

set_value

but this only works upon a reload, not a redirect. Upon submiting the data to go into the preview page, I create a unique identifier. I was thinking that I could use that in repopulating the fields, but I am unsure how to do this.
Thanks for your help.