Adding Supplier to Asset

We are loading old Fixed Assets via web adi into fixed assets. The supplier field is not on the web adi spreadsheet. Even though the supplier number is on the spreadsheet, the supplier name does not appear in the Prepare Mass Additions work bench and when we post the supplier name does not appear on the source tab of the asset and the field is not enterable. Does anyone know of a way we can easily get this information in the record. For equipment it is important that this information be included.

Thank You