I’ve to correct my answer; the Cytron in the steer.png confused me…
I’m using a circuit like the IBT-2, so the DIR1_RL_ENABLE = D4 is the signal to control the 6/2 valve. It can be found here (underneath the yellow “D1” text):

I also found an “old” link discussing the same topic: Hydraulic valve info from Telegram group - #90 by Richardklasens_admin
There is another option I would prefer: Just add two lines of code, copying the D4 bit to the D5 bit and use the signal available at the “Steering” connector:
