Impossible to remove left turn signal

[alibaba]

2009 696 have to remove and replace left rear turn signal.
Have removed lens and reflector and bulb - wires disconnected.
Looking inside with flashlight for bolt head or screw to remove the black plastic assembly.
All I see in there is what looks like a flat, round bolt head.  No way to get a tool on?
To get on other side of mounting point it looks like half the bike has to come apart.

What is the trick?

[alibaba]

Finally solved.  To get at the small Allen bolt holding on the turn signal is a total PITA.
The 'plate' they are mounted on  must be removed.  The 4 bolts under the seat thread into 4 Allen headed 'nuts' under the mounting "plate" and accessing these is not easy.  The wrong place to use Allen head fasteners.  Fiddling up under the seat to these recessed 'nuts' makes an easy job more difficult. 
Same problem with Allen bolts under the 'plate' to remove it.  Bad design.   
Common problem is a broken right side turn signal breaking off as the leg contacts it when mounting the bike.
All together a difficult job to replace a common item.  You know the designer never had to replace a rear turn signal. 

[stopintime]

All that just to hide a few screws  They probably think that hiding screws makes the bike better looking. Maybe that's how it has become...

The ever more popular "Contact your dealer"