[ALUG] Scripting a crontab re-read

Does anyone have any idea how to force cron to reload its user-based crontabs? I have a setup script for a system which does a lot of things, amongst them copying a crontab into /var/spool/cron/crontabs and settings its permissions, however cron ignores it until I crontab -e and make a change (eg add and delete something) and save it. Restarting cron or even the box is not sufficient to make it reload. I discovered that the mtime of the crontabs folder is relevant, but "touch"ing it hasn't solved the problem. (System is Ubuntu 8.04 server.) -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0845 45 89 555 Registered in England (0456 0902) at 13 Clarke Rd, Milton Keynes, MK1 1LG