I stick my to the headstock with some clear fablon :cool:

inside the fairing secured by the screw that holds the fairing on from underneath, ie its sandwiched between the fairing and the air tube

In my pocket!!!
 

what's this tax disc thingy ?

Under the seat, or where the airtube bolts up to the headlamp bucket

...on the subframe, behind the foot pegs. got one of those metal hexigan shaped disc holders and screwed it to the bike. works well.