No, the on and off button refer to button 1 (group 1), and A=3, B=4, C=5, D=6. If you convert to an 8-button pad, the numbers will be 1-8 = A-H (there are two microswitches under the large on and off buttons that can be controlled by individual small buttons). If your keypad is the controller of the scene then the A button will be group 3. You will need a link in the keypad to control each device in the scene that has Group=3, and then Data= 00 00 00. The links in each device in the scene will have the keypad as the controlling device, Group = 3, and Data = FF 1F 00 for a full-bright/fast-ramp (0.1 sec) response.
Hope that helps.