How to default DFFs value already configured at the Transaction Source end

Summary:

We have a requirement to display some DFF values that are already set at the Transaction Source end.

While creating an AR Transaction, based on the transaction Source that we choose, we wanted the DFFs to be displayed at the time of Invoice Creation.

How could be achieve this.

Content (required):

Screenshot Transaction Source shows the Yellow highlighted fields defined as DFFs while setting up the transaction Source.

How could these values be populated again at the time of Transaction creation.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):