[preserve file ownership on sync]

I also followed the owncloud/btsync setup for the raspberry. I use the following autostart script to launch btsync:

#! /bin/sh
# /etc/init.d/btsync
#
# Carry out specific functions when asked to by the system
case "$1" in
start)
    start-stop-daemon -c www-data:www-data --start -x /home/pi/.btsync/btsync
    ;;
stop)
    killall btsync
    ;;
*)
    echo "Usage: /etc/init.d/btsync {start|stop}"
    exit 1
    ;;
esac
exit 0

This starts the service as user www-data and group www-data, the executable is at /home/pi/.btsync/btsync

It still doesn't preserve the permissions (somehow I'm getting 644), but it's close enough. Would be great if a default umask could be set somewhere. Right now I just have a cron-job keeping the permissions intact.