WHile uploading to S3 can we make the sign call with method 'POST' instead of 'GET"?

Trying to make a /sign call for S3 upload to be a 'POST' one.
But call does not change when method : 'POST' is sent in creation of S3Uploader.

` uploader = EmberUploader.S3Uploader.create({
        url: this.get('url'),
        method: 'POST'
      });`