Matrix metering with Tamron P/KA ?

[Andre Langevin]

I understand Tamron P/KA mount is a cripple A mount because its basic 
mount contacts do not provide information on the maximum and minimum 
aperture of the lens, which is necessary for matrix metering.

Is it possible to modify the mount (for a particular Tamron lens) to 
provide the camera with matrix metering for that lens?

Is matrix metering possible with an A lens (Pentax or Tamron) that 
has not a constant aperture?

Andre