BAPI_ACC_INVOICE_RECEIPT_POST Negative sign not updating for positive amount document

[Vasutm]

Hi, 

Using BAPI_ACC_INVOICE_RECEIPT_POST, I am trying to create an accounting document with a positive amount and a negative quantity. 

Despite the BAPI posting the correct positive amount, but the quantity is posted with a positive sign.

It would be appreciated if you could tell me how we can achieve create accounting document with negative quantities for positive amounts. below is my values passing to BAPI structure.

Amount is 8 dollars and -1 quantity.