dynamic send to with select box

Hello, I created a contact form with a select box with four options in which the value contains the email address to send the message to and the description is just a textual representation. I assigned the name send_to to this field and put [user_send_to] into the to field of the submit option panel. When I try to submit the form I got the error that at least one address must be provided. I added my email to the recipients and put the [user_send_to] into the email text and saw that it’s blank. Also the [form_data] tag contains the description of the chosen option (not the value). I’m doing something wrong? In more general terms how can I access the value of a option field?