Performance Issue in PO attachments - Bulk upload

Summary:

We're attempting to attach TEXT and FILE attachment types for PO attachments via the SOAP UI, but the attachment API processes each line individually.

The processing time for 100 rows of combinations of the TEXT and FILE attachment types for PO attachments is five minutes, and the attachment has been attached at the PO header level.

(For instance, 1000 rows at a time.)

For purchase Orders, we need to attach nearly 45K rows that are a combination of TEXT and FILE attachment types. which would be time consuming .

So is there an API or bulk import process available for uploading attachments in PO?