After apt-get install -y kstart, we can put in a script that runs through pam_exec:

su ${PAM_USER} -c 'kill $(cat /var/tmp/krenew.${USER}.pid) ; /usr/bin/krenew -Lb -K10 -p /var/tmp/krenew.${USER}.pid'|logger -t "lwp-request-homedir"
      

that 'll keep the user in touch with his homedir.