Hi,
Mounted a Midas LCD on my MB6582 and I remember that I encountered the same problem...
I first made the "standard" wiring and burned the backlight...
Figured it out (after having bought a second LCD :/ ) by simply following this little scheme in the spec :
... and made some rewiring around P2 trimmer :
Finally, check the wiring on LCD side. Pins 15 and 16 should be inverted, but double check with the LCD pinout.
Hope that will help you.
Cheers!