[Plugin: MailPress] Dedicated Unsubscribe button

Is it possible to put an “Unsubscibe” button or link on the widget? Say, right below the “Subscribe” button?

It would be convenient/is necessary just to provide my e-mail address and then unsubscribe without “managing” my subscription – which is impossible on my site because I don’t use any registration system: consequently there is no such link as “Manage subscription”… so there is no way to unsubscribe.

Hm? (Or is it already implemented and I am blind…)

Thank you in advance!