Vertical speed variable

[maxx]

Hello,

I'm trying to map TBM 850 autopilot controls on my Winwing FCU using Mobiflight.
So far so good, the only data I can't extract from the sim is the selected vertical speed value.
I thought A:AUTOPILOT VERTICAL HOLD VAR worked, but it always returns zero.

For sure I'm missing something.... any hints?

Thank you very much.
Massimo