When creating a rule in a project template, two types of Asana elements are not available to be used as part of a Trigger, Condition, or Action: custom fields and sections.
This is not due to any limitations on Flowsana's part, but rather is due to a limitation of Asana: it does not make available a project template's custom fields or sections to external integrations. Thus Flowsana has no way of knowing or determining what custom fields and sections exist in the template, and so we can't provide them as part of our rules.
We have been pushing Asana to rectify this limitation; so far we have been unsuccessful, but we continue to push!