Anyone here who might know howto setup screen so it does also work for jaild users? Now when I login as a shell user on my Debian Lenny server and type screen I get a "bash: screen: command not found" error.
Did you copy all of screen's dependencies (libraries and so on) into the jail? Maybe you can use the create_chroot_env script from http://www.howtoforge.com/chroot_ssh_sftp_debian_etch for this.