FortiVoice 300-E - Direct Call (Hotline)

Hi, I want to configure an extension as a RingDown (Hotline), here's the steps that I used to go thru to configure it:  In the menu I chose Extensions then Extensions, then I clicked on Managed Extensions tab then I chose the extension number that I want to configure as a hotline. Once inside the extension properties I clicked on "Edit Preferences" and scroll to the bottom of the page and I enable the Direct Call box and I write down the extension number that  I want to call automatically when the handset is picked-up . I did this but the extension continues with the dial tone without dialing the configured number. What step I skipped? There's other step I have to do to make it work?