Below is from the MKS manual. Pretty sure the SHO is the same. There should be a slot in the glove compartment.
Backup Method of Starting: Your
IA key uses a radio frequency signal
to communicate with your vehicle
and authorize your vehicle to start
when you press the START/STOP
button and apply the brake pedal. If
excessive radio frequency
interference is present in the area,
or if the battery in your IA key is
low, it may be necessary to start
your car by inserting the IA key in
the backup slot, located in your glove box. Insert the IA key into the slot
with buttons facing out and with key ring up.