How to disable the skip courses which are unavailable and have not been changed in the certain time..

Hi there:

I would like to backup all courses without any skipping on my archived course site with Moodle 2.2.4.

But I can not find anyway to set it  by setting "Courses"-->"Backups" --> "AUtomated backup set" as Moodle I can do at 2.6.x.

I guess I need to modify some code soemwhere at backup/lib.php or other place like <Moodle 1.9.x;

Any help on this issue?

Thanks.

Andy