S3Uploader: ability to set more headers

Currently, you can only set the Content-Type when uploading a file using the S3Uploader transformer.
According to the S3 REST API documentation, there are also other headers to set, like Cache-Control, Content-Disposition, Expires etc. It would be nice if (a selection of) these can also be set by the S3Uploader, similar to the HTTPCaller. I could of course use the latter to achieve what I want, but the S3Uploader sure makes authentication a lot easier..