DMU50 Traori Singularity Minus B movement

Hi,

Our DMU50 allows for -5 degree's in the B rotary axis.
When I program a 5-Axis toolpath to utilize(up to) -5 degrees, the table rotates around 180, and doesn't go minus. The B will always stay positive, even though the program shows minus B numbers.
I assume this is TRAORI transforming minus B values to C rotary motion.
Is TRAORI(2) what I need? I don't understand how TRAORI Is different than TRAORI(2).
Or, could this be a soft limit in the control somewhere?