Is it possible to POST values to another page from the FORM SUBMIT function
It sounds like you are doing a multi step form (given the URL in your form is "confirm"). You don't want to be looking at $_POST values, you'll want to utilize FormAPI all the way through.

See for examples:

http://www.sitepoint.com/building-multi-page-wizard-like-form-drupal/

http://jamesdavidson.io/blog/how-create-multi-step-form-drupal-7

http://www.webomelette.com/ctools-object-cache-multi-step-form