Adding backup/restore settings in a local_ plugin?

Hi:

I'm trying to move hacks in the core of moodle that we have been adding in my university's customizations of moodle into isolated and wel defined standard plugins.

I need some custom global settings when restoring courses ¿is there a way to introduce settings in backup/restore task from a local plugin?

I 've tried to add a define_my_settings() method to the local restore class, but I do not see a checkbox in the interface to control the setting when restoring a course, as expected. It seems that method in a local pluging is not called ¿is this correct? ¿Is there any other way to add new restore settings to a course restore task (not using a custom course format)?