Use a redirect header targetting to the other script along with the http-status code 303 (means "see other"). In the URL you must suplly with -uri you can easily add an ID as a reference to the document you created or identify the user in any other way. merlyn wrote a column about Browser Branding.

Have a nice day
All decision is left to your taste

Update

Regarding the format for that temporary file I'd suggest you look into XML::Simple, or if you can be sure the user will proceed immediately you could _store_ a hash with some values in the first script, pass an identifier to the second script which then _retrieve_s the hash using methods from Storable.pm.