Subject profile : Subjects, Reasons, categorization schema

Dear Experts,

For a service ticket I need to create subjects, reasons as well as categorization schema.

For the subjects, I have created the subject profile and have assigned it to the Service BT category

For the reasons, I have created the subject profile and have assigned it to the Business Activity BT category.

Since there is already a subject profile assigned to transaction for service; how would I assign the subject profile for the categorization schema?

Thanks & REgards,

Kanthimathi