I just modified the /opt/bitnami/ctlscript.sh to include both celeryd and celerybeat at the startup.
First you have to daemonize celery, as in this tutorial.
Running the worker as a daemon
After all, WITHOUT updating rc.d to start up the daemons, execute from the shell
sudo mkdir /opt/bitnami/celery/scripts
sudo ln -s /etc/init.d/celeryd celery/scripts/celeryd
sudo ln -s /etc/init.d/celerybeat celery/scripts/celerybeat
You cannot use these init.d scripts to be run simply by run.d, because they will start before MySQL starts. So, you have to call these scripts from the bitnami ctlscript.sh script.
Here the modified version of ctlscript.sh. I couldn't upload it.
Hope it works well!