STAIR AC22 upper and lower connecting structure?

[BPETER]

I`m missing the subfloor plus finish thickness control-ability. In the past there was an option to choose the thickness of connecting slabs, now in the new stair tool we have a lot of option but this one is missing . I`m able to set these values for the upper connection with no problem...... but in the lower part i can`t and i can`t figure out a workaround.
The problem is that when i start a stair with riser i have no tread to control the TREAD GAP and the first tread is controlling the first 2 tread gap,

I NEED TO CONTROL ONLY THE FIRST ONE, if stair is starting with riser than remove the tread gap or give me an option to control it, like i can control it at the top.
What am i doing wrong? or how can i solve this?