Setting custom encoding for a single request?

Hi all,

I was wondering if it's possible to set Rails's output encoding for a single request w/ Ruby 1.9?

For example, one request on my app generates a form for submission to a third-party who mandates ISO-8859-1, and the form therefore contains iso-8859-1 encoded strings.

Although I set the response's content-type to 'text/html; charset=ISO-8859-1', when Rails renders the output it produces a UTF-8 string (containing ISO-8859-1 characters) and then falls over with an "ArgumentError (invalid byte sequence in UTF-8)".

Is is possible to tell Rails "generate all output for this request in charset x?'

thanks, d