Outer Limits 4x4 Board

I have a 1989 import Pajero 2.5 turbo diesel.....Runs great but has side mirrors ideally suited to drivers around 5ft tall..!! The mirrors swivel just fine left to right, but the up and down tilt adjustment relies on sliding the mirror up or down on the tubeular bar that runs from the top of the window frame to the door panel and the adjustment is hopeless if you're a driver around 6ft tall. Has anyone encountered this problem??...if so how did you fix it??.....Is there a generic replacement available??