Thanks for this very detailed reply. I made all entrys in the template.php and user-profile-form.tpl.php and cleared all cache multiple times. Unfortunately the edit site does not change. Iam confused about the $items['user_profile_form'] keyword - is there any reference, because in other forums i read something about $items['user_profile2_edit']?
I keep on trying and will reply as soon as it works! Thx