Merchant Fields

Hi,
Somebody knows  if it is possible to add more merchant fields to use for reporting proposals?

The user guide list the following:

Merchant Name - The name of the supplier.

Merchant Receipt Number - The receipt number for this expense line.

Merchant Tax Registration Number  - The supplier tax registration number.

Merchant Taxpayer ID  - The supplier taxpayer ID number.

Merchant Reference - Additional supplier reference, such as contact

Additionally, which are the reports in which appear this information?

Regards,

Veronica