Unable to reference [[CustomerReference]] field for the condition Run this workflow when sale pack is authorized

I am setting up a workflow automation that triggers when sale pack is authorized.  The event is notifying the customer via email that their purchase order is ready for pick up.  We use the field [[CustomerReference]] to input the customer's PO number, and I would like to reference that in the email subject line.  We would also find it useful to reference [[ShippingNotes]] in the email body.  We use that field for the pallet dimensions, which the customer needs to schedule a pick up.

The placeholder fields when sale pack is authorized are pretty limited.  My request is to make [[CustomerReference]] and [[ShippingNotes]] available as placeholders when ‘sale pack’ is authorized.

Does anyone have any workarounds or would anyone else find this feature addition useful?