Hi again,
Is there a possiblity to set SYSTEM-WIDE a pinentry for gpg-agent? I have solved the upcoming issue by adding the line
pinentry-program /usr/bin/pinentry-qt
to ~/.gnupg/gpg-agent.conf
but I have to do that manually for all users. Same home directories have worked using Debian flawlessly. You see: I am migrating everything to Arch and now there are some small incompatibilities 
Regards
df8oe