I would also be very interested in this! I've done some research and haven't found anything - it's really annoying that you always have to select the HDMI connection.
The Panasonic TB-40S45AEZ weighs 6 kg without stand and has a VESA compatibility of 100 x 100 mm. The Goobay Basic L TV presentation stand supports screens up to 35 kg and is compatible with VESA standards of 100 x 100 mm. Therefore, the TV should be able to be mounted on this stand as the weight and VESA requirements match.