To finish this, I had to associate the Service with the Favorites Web Service: Logon tModel. Under Specification Signatures, select "Add specification signature." To look the model up by name, enter "Favorites Web Service." This will bring up all three of the tModels saved for the Favorites Service. Select "Favorites Web Service: Logon" and press "Continue." A Web page then appears on which you need to edit some more information about the endpoint. I filled in those fields as follows: