Outlook web addIn dropdown menu

I have created the Outlook Web Add-in project and trying th create the dropdown menu by following the link under

http://ift.tt/2uFWK0H

It seems that dropdown menu just take static list. What i want to do is i have webservices which is returning some destination and link of that destionation . I want to display the list of all those destination under the dropdown and by clicking one of it, it opens the link into task pane. Any tips ? how to display from webservice in dropdown menu.