Hi, Rich,
sorry for the delay in answering - due to work an a flue...
I'm running Core 4.5.5. I think Hardware is not relevant since I tried it on several PCs meanwhile. Nevertheless the configuration is in the attachment.
But meanwhile I'm in another problem. I managed it do get Xorg running (using a former version of the environment where Xorg wasn't installed already) - and the problem with the not or wrong accepted keys is gone...
But now I have another problem: In terminal session - connected to the windows server - it acts rather slow - like having a 64k modem connection - but I'm in a local environment, connected via ethernet connection or wifi with optimal signal strength.
So maybe Xorg is not a real solution for me because no one can really work with that screen updating speed...
Back to the arrow key problem:
One difference between the Xvesa and the Xorg installation is that now - in the Xorg environment - the "standard" keyboard layout is installed. In the Xvesa environment I managed it to get a german keyboard layout running. Maybe that was the reason for the wrong key translation in remmina?