How to edit data of subscribers

Hi,
this module is so good - thank you for it.
I have one little problem: sometimes people call me and want to change something in there subscription data. I normally use the "mass subscription" to update data. But it is not very comfortable AND I can't modify the email address. Yesterday someone called me, that he has a new email address.
Is there a way to add also the user information on the edit form. The subscribers are NOT synced with the drupal user system.

Kind regards

Kai