Charset encoding @ RestWorkItemHandler

Currently it's not possible to send content with POST or PUT methods in encodings other than default ISO 8859-1 - non-latin characters become question marks on the wire. So it would be great if RestWorkItemHandler could set encoding for HTTP client either directly via corresponding parameter or as a result of ContentType parameter analysis when it's value contains the necessary information (e.g. "application/xml;charset=utf-8").