1989 PX 125, upper rear shock mount failure

Hello folks, quick question, 1st post here. PX 125 1989 upper rear shock mount, is corroded and failing. shock is beginning to come through under the seat pan, behind the gas tank.  It seems I will have to fabricate a new bracket and weld it in place from underneath.  Does anyone make such a bracket?  If not, does anyone have an idea of the sizing, dimensions of a bracket. Any other suggestions on repair?