I'm not Umberto, but I asked the same question some days ago. At the moment it is not possible for the user to define which kind of fueling system is available. The dispenser will arrive at jetway-equipped positions, the classic fuel truck will arrive at remote stands. Umberto said that a functionality to define the refueling type will be added with the next update. I appreciate that very much, as there are a lot of airports without underground refueling systems, and also a lot of airports which use underground refueling even on remote stands.
I hope that functioniality can be added very soon with a small update. The easiest way would be a simple tick box in the gate customization menu where you can define the refueling types available for each stand.
