SAP River - Call an action passing a Stream

Hey River early adopters,

Here is my scenario:

I created an action like this:

@OData

application myApplication {

     action testStringStream (ss: String[]): String{

            let messageReturn: String = '';

            foreach(item in ss){

                 messageReturn = messageReturn + item;

            }

            return'Final: '+messageReturn;

       }

}

To call this action I checked the auto-documentation generated in:

               myServer/sap/hana/rdl/odata/docs/myEnviroment/myProject#myApplication.testStringStream

and it gave me the following Request body:

               { "ss": <StringValue> }

but, making a HTTP Post with this request body, it returns the message:

               "type": "ODataInputError",

                "message": "Bad Input: Problem with action parameters types"

I've tried several different ways to make that call but I keep getting the same error...

The question is: How is the right way to pass a Stream type in a HTTP POST request body when calling an action??

Thx!

Rodrigo