Android cannot serialize byte[] recieved from compressed BMP

The code

Bitmap bmp = (Bitmap)extras.get("data");
ByteArrayOutputStream out = new ByteArrayOutputStream();
bmp.compress(CompressFormat.JPEG, 100, out);
byte[] raw = out.toByteArray();
PassToWebservice(raw); //error

PassToWebservice(byte[] ba)
{
   SoapObject envelope...
   envelope.addProperty("base64bytes", ba);
   ...
   transport.call(ACTION, envelope);
   envelope.getResponse() //error: IOException cannot serialize...
}

The problem

When I pass the compressed image to my webservice, I get a runtimeexception that says "cannot serialize [B@47bcb6c8..." Something is not apparent to me, can anyone see why the above (psuedo) code does not work? If it helps, on the webservice server side, the exception seems to be happening when the server writes the passed bytes to a file (using开发者_StackOverflow .Net IO.File.WriteAllBytes)

Stack trace

I needed to do this:

MarshalBase64 marshal;
marshal.register(envelope);

SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);

        new MarshalBase64().register(envelope);   // this is will over Cannot serialize: [B@f034108 

        envelope.dotNet = true;
        //Set output SOAP object
        envelope.setOutputSoapObject(request);
        //Create HTTP call object
        HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);

        try {
            androidHttpTransport.call(SOAPACTION, envelope);
            SoapObject response = (SoapObject) envelope.getResponse();