As we are not working with the drupal messages variable, we want to have the confirmation in a different page OR to replace the form. I have been searching through all of the request and always i ended up with a dead end.
I installed rules to see if could do a redirect after a subscribe, but i got stuck providing a mail Data Selector tpye mail.
After that i tried to overwrite lists_block_view in a custom module to check for the $message and then show the message instead of the form, but this would interfere with the error message where the form should be there.
Does anyove have a pointer to have a page for confirmation after a user subscribed?