Added attachments via API to a supplier invoice are not visible

Hey,

We need to add attachments (pictures or links to pictures) to a supplier invoice. When using the API from https://api.sap.com/api/API_CV_ATTACHMENT_SRV I can succesfully post both documents and url's to an existing supplier invoice.

I will even get the number of attachments when trying the API_CV_ATTACHMENT_SRV/GetAttachmentCount. This would mean that the object in question has those attachments.

{
  "d": {
    "GetAttachmentCount": {
      "__metadata": {
        "type": "API_CV_ATTACHMENT_SRV.AttachmentsCount"
      },
      "AttachmentCount": 6
    }
  }
}

BUT when I go to the tile for supplier invoices, doesn't matter if it's the standard or advanced one, no attachments can be found. This same API has also been tried on materials and attachments are showing up without any problems.

Does anyone else have any experience with this problem?

Kind regards,

Thomas

Solution:

After digging in the api.sap.com hub and hounding our friends at SAP I have found an answer: "attachment service for supplier invoices is not supported in SAP S/4 HANA 1808. With 1811 this is possible with communication arrangement SAP_COM_0057". It is possible apparently to hack this in the API hub but don't try it via postman or any other of your favorite REST clients. Check my other comment below for more info on the specific query you'd need to execute.