Energy Tab - add energy_buy statistics

HI!
I am a´very keen on using the the new energy tab.
I integrated my energy production from my photovoltaic system:


coming from the sensor:

also the energy sell value works with this sensor:

what is not working is the completely analogue set up energy buy value:


It is not even shown in the setup dialogue in the energy configuration…
What should I change?
Thanks for suggestions…