Barcode Soap Webservice

I’am trying to consume this Barcode generating Soap Service:

Inside the soap Setup i use:

The service API Docs are available.
As requestbody i think i have to send something like this:

“BarCodeText”: “1356544”,
“BarCodeParam”: {
“barcodeType”: “Code128”,
“Width”: “10”,
“Left”: “5”,
“Top”: “5”,
“BarCodeImageFormat”: “PNG”



The result should be a base64encoded string, but
I get the following error:

“error”: {
“context”: null,
“message”: “The Response content must be a string or object implementing __toString(), “boolean” given.”,
“code”: 500,
“trace”: [