Selected recipient

please take a look at my form at http://h-y-p-h-e-n-s.net/contactus1.html ( ignore the broken images )
i want the recipient to be the selected option in the “department” field.
but when i put the value of the hidden field"recipient" as “department”, it failed to work…

but if i just put the hidden field"recipient" as "me@h-y-p-h-e-n-s.net", it works…

how do i make the form send the emal form to the recipieent in the selected “department” option?