Can't POST binary file via SoapUI but works fine via cURL and Postman

I use SoapUI-5.3.0. My curl request with only a binary file as attachment works fine (see below curl output). It also works fine in Postman (Google Chrome plugin). But it doesn't work in SOAP UI and throws the error "400 Bad Request: cannot parse incoming googlebuf".

I attached the binary file using the attachments tab in the REST Request window. How to fix this problem ?

$ curl -X POST --data-binary @rrs.gpb https://<REST URL> -v
Note: Unnecessary use of -X or --request, POST is already inferred.
* Trying 104.40.49.176...
* TCP_NODELAY set
* Connected to <URL> (<IP>) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
* Server certificate: SHASTA-RRS.SYMANTEC.COM
* Server certificate: Symantec Class 3 Secure Server CA - G4
* Server certificate: VeriSign Class 3 Public Primary Certification Authority - G5
> POST /mrclean HTTP/1.1
> Host: <Some URL>
> User-Agent: curl/7.51.0
> Accept: */*
> Content-Length: 136
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 136 out of 136 bytes
< HTTP/1.1 200 OK
< Keep-Alive: timeout=5, max=50
< Content-Length: 80
< Server: Microsoft-IIS/8.5
< Set-Cookie: <Some Cookie>
< X-Powered-By: ARR/3.0
< X-Powered-By: ASP.NET
< Date: Fri, 07 Jul 2017 12:36:43 GMT
<
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�p@��r��t�l�D �ˆ�Ȑ��s�R!+� (0
:@HX��px�
* Curl_http_done: called premature == 0
* Connection #0 to host <Hostname> left intact
$