How ca we edit those fields price and quantity field for a document with source in expenses?

Summary:

There is process and a legal report in Ecuador (Called E-Settlement) that needs to be sent to tax authority SRI . However, this legal report has a mandatory to show and send information for quantity and Unit Price. For manual or matched invoice those fields are filled but when the document has source in expenses it is not possible to update those fields with information because are grayed.

How can we edit those fields to include any value in price and quantity field by default and sent the legal report with information? It is a legal request with tax authority and it has not been possible to send information related with expenses