Two Textarea Elements in wp-admin/page.php?action=edit&post=

I am writing what I thought might be a simple plugin to add a second textarea to the edit page. I hook into my function with ‘edit_page_form’, and my form with textarea shows up fine. My problem is that on form submission my ‘if(isset($_POST[‘etcetc’ …] script for the second textarea seems to be entirely bypassed, the ‘wp-admin/edit-pages.php’ is returned, and no mysql updates/inserts are actioned. Any suggestions as to what it takes to propely add the second textarea would be greatly appreciated.