Need to add detail to the subject line of enrolment request but can't find the attributes in BPM

Summary:

Hi

We would like to add some more information to the subject line of the notification for learning enrolment but are not able to identify/find the data fields as part of the task payload. Can anyone suggest how to find these if this is even possible?

Content (required):

We have extended the data model for the notification and can add the added data to the layout of the approval request message but we would like to also add details to the subject line (department and employee number). In BPM when configuring the subject line we are not able to find the fields we have added (nor most of the standard fields). Can anyone advise how to find the mapping? Or advise if this is even possible?