Required Dynamic Insertion of few fields in Email Subject and Body for Dunning Letters and Statement

For Customer Statements, Currently on Customer Statement E-mail's Subject and Body, information is being picked up from Receivables System options and printing as Static data.

For Dunning Letters, Currently on Dunning Letter E-mail body, It is being picked up from Collections Preferences and printing as Static data.

The requirement is to insert dynamic fields values like Customer Account Number & Customer Name in Customer Statement email subject and Body of the Email, and E-mail body of Dunning Letters, Explained the requirement in attached word document in detail.

By following Oracle Document "How to Customize the Email Subject and Body for Dunning Letters? (