redirect_to's and http_accept

When I have a redirect_to in an action, the http_accept doesn't seem to
get passed. For example, if I am using respond_to to detect js, which
then redirects to another action, my http_accept header doesn't get
passed during the redirect. If I want the new action to respond_to a
js, it doesn't get triggered.

any body else seen this and if so, how do you deal with it?

Thanks,

Steve