Issue in Attachement Transfer from SRM TO ECC for ECS

Hi All,

          We have a requirement for Transfer of Attachment information from SRM PO to ECC PO in Extended classic scenario.

          So we have implemented BAdI  - BBP_ECS_PO_OUT_BADI and implement the method BBP_B46B_PO_OUTBOUND.

          We have used  function 'META_ATTACHMENT_CREATE' to  create attachment in ECC.

          We are getting Error on FM. On debugging i found out error message as

          The link to SAP object is not allowed for document type SRM .

          Kindly help us to resolve this issue. Is any config we are missing or correct  parameters are not passed to FM .This message is from ECC side.

   Thanks and Regards,

   Aditya