OEM 13.5 - How do you add a multi-task corrective action to a database metric warning or alert?

According to the OEM 13.5 docs, you can create a multi-task CA (and each task can perform a task against a different target type). I have created a multi-task CA so that upon a database metric warning or alert, OEM will kick off an OS script on a separate server to the database server that gets the warning or alert. However, when I go to the metric and try to add the CA, it is not listed although it has been saved and published. I see that for any multi-task corrective action in the library I have created, its target