Here it is: after I found this inexpensive pressure sender Pressure transducer or sender, 100 psi, stainless steel, for oil,fuel,air,water | eBay
I done a little module to use it with the oem "fake " gauge.
It reads from zero to 100 psi, around 7 bar.
Easy to install, just screw three terminals to the back of the gauge and route three wires to the pressure sender.
If you want to add a warning light, the module is prepared to turn it off when it reaches 14.5 psi, just like an oem light
I chose this location for the warning led:
A short video:
module - 30 euro
high lum. led with "titanium" mounting hardware - 2 euro
pressure sender (link at the top) - 18 USD
1/8 bspt male to 1/8 npt female costs a few cents from you local hydraulic shop
the module screwed at the back of the dash:
pressure transducer and npt to bspt adapter: