How can you restore the dump image finally?
I personally wouldn't include the mysql-stuff into afbackup configuration files.
I would do the following instead:
Do a "mysqldump --user=backup ...--all-databases.. > /path/to/a/directory/mysql_backup.sql
before running afbackup. Replace "/path/to/a/directory" with a directory that is backuped up by afbackup.
This way the mysqldump is just a simple, plain file in your backup.
You can later restore the database with
mysql < mysql_backup.sql