Output von Mises stress in TH file

Hello all,

i need to output the maximum von Mises stress value over all of a shell elements integration points.  

I looked in the manual under /TH/SHEL, but can not find vM-stress, nor global stress components output options.

Furthermore, i am uncertain about the Output option F1, F2. In the manual it is noted, that these give output of stress in direction 1 and 2, but is this regarded to the local element frame or to the principal stress directions?

Thanks in advance