I see, the relevant table is this smf_helpdesk_custom_fields_values, then you will need to edit function shd_main_helpdesk() in SimpleDesk.php and finally the template to show it up. arantor would easily be able to do it, but he mostly disappeared from the net :/ My php knowledge may not be enough to figure out how to do what you ask, I'm just replying to tell you, because I am about to go to lunch so I can't really take a closer look at it and eventually try to code it at the moment.
Maybe enabling the email notifications is a good idea.
Maybe enabling the email notifications is a good idea.