[resteasy] Resteasy multipart filename

Hello, I'm using Resteasy client to upload files to a service. I can set the filename using the @PartFilename annotation: @FormParam("file") @PartType(MediaType.APPLICATION_OCTET_STREAM) @PartFilename("staticfilename.bin") public InputStream file; But this sets the filename at compile time - how can I make this dynamic?