[CA] Shared Charts on 2 MFD in one network

Hi,
after having been struck by lightning (in Panama), we had to replace our entire Navigation and we decided to go for a complete Raymarine solution.
OK, now that except for the depth transducer everything is installed (Axiom 12 pro s, Axiom 7, Evolution 400 ... HSS, ITC5, Quantum), I was hoping that the two MFD's would share the Charts.
The network seems to work OK and waypoints that are entered on the Axiom 12 (Datamaster) appear on the Axiom 7 as well.
What does not seem to work is that the Charts (microSD in the Axiom 12) are also used by the Axiom 7.
I am sure that is it only a tick box which I may habe missed ... but so far , I could not find it.
Please, maybe one of you may know why the Charts are not showing on the second MFD.

Thanks,
Joachim