Spring ResponseEntity

I have a use case where I need to return a PDF to a user which is generated for us. It seems that what I need to do is utilize the ResponseEntity in this case, but I have a couple of things which are not very clear.

1. How can I redirect the user -- let's pretend they don't have the permissions to access this page? How can I redirect them to a separate controller?
2. Am I able to set the response encoding?
3. Can I achieve either of these two without bringing in the HttpResponse as a parameter to my RequestMapping?

I'm using Spring 3.0.5. Example code below:

@Controller
@RequestMapping("/generate/data/pdf.xhtml")
public class PdfController {

    @RequestMapping
    public ResponseEntity<byte []> generatePdf(@RequestAttribute("key") Key itemKey) {
        HttpHeaders responseHeaders = new HttpHeaders();
        responseHeaders.setContentType(MediaType.valueOf("application/pdf"));

        if (itemKey == null || !allowedToViewPdf(itemKey)) {
            //How can I redirect here?
        }

        //How can I set the response content type to UTF_8 -- I need this
        //for a separate controller
        return new ResponseEntity<byte []>(PdfGenerator.generateFromKey(itemKey),
                                           responseHeaders,
                                           HttpStatus.CREATED);
    }

I'd really like to not pull in the Response... None of my controllers have done so thus far, and I'd hate to have to bring it in at all.