def _create_set_property_msg(self, prop, cmd, val):
        """Create an extended message to set a property.

        Create an extended message with:
            cmd1: 0x2e
            cmd2: 0x00
            flags: Direct Extended
            d1: group
            d2: cmd
            d3: val
            d4 - d14: 0x00

        Parameters:
            prop: Property name to update
            cmd: Command value
                0x02: on mask
                0x03: off mask
                0x04: x10 house code
                0x05: ramp rate
                0x06: on level
                0x07: LED brightness
                0x08: Non-Toggle mask
                0x09: LED bit mask (Do not use in this class. Use LED class)
                0x0a: X10 All bit mask
                0x0c: Trigger group bit mask
            val: New property value

        """
        user_data = Userdata({'d1': self.group,
                              'd2': cmd,
                              'd3': val})
        msg = ExtendedSend(self._address,
                           COMMAND_EXTENDED_GET_SET_0X2E_0X00,
                           user_data)
        msg.set_checksum()
        self._set_sent_property(prop, val)
        return msg
Create an extended message to set a property.

        Create an extended message with:
            cmd1: 0x2e
            cmd2: 0x00
            flags: Direct Extended
            d1: group
            d2: cmd
            d3: val
            d4 - d14: 0x00

        Parameters:
            prop: Property name to update
            cmd: Command value
                0x02: on mask
                0x03: off mask
                0x04: x10 house code
                0x05: ramp rate
                0x06: on level
                0x07: LED brightness
                0x08: Non-Toggle mask
                0x09: LED bit mask (Do not use in this class. Use LED class)
                0x0a: X10 All bit mask
                0x0c: Trigger group bit mask
            val: New property value