How to send JSON and receive binary via http post

Hi everyone,
is there a way in thingworx to make a http post request with JSON or text content to an external service and receive a BLOB?

// result: JSON
var result = Resources["ContentLoaderFunctions"].PostJSON({
url: "http://xyz:8080/createFile",
content: {"filename":"test"}
});

Things["MyRepository"].SaveBinary({
 path: "/",
 content: result 
});

The PostJSON method expects a JSON response but we would like to store the received binary in a file repository.

Is there a more generic way to make HTTP requests or do we have to create a extension for that.

Thanks