You need to do two things before they can be programmed:
1. Go to the Expansion Module section of the phone configuration page and make sure it's enabled there.
2. Go to Device - Device Settings - Phone Button Templates, go to the standard 7961 one (or whatever is assigned to the phone) and copy it. Call it something like "7961 with 14SD".
3. Configure the softkey layout, being mindful that buttons 1-6 are on the phone itself. Button 7 corresponds to the first button of the sidecar and so on. Assign the role of these buttons to Speed Dial. Save it.
4. Go to the phone configuration page and change the Phone Button Template to the new one. Save and reset the phone.
5. On the left hand side, click on any Speed Dial button and you'll see a child window appear- you can configure the speed dials in there.