Redirect_to is changing my webpage charset

Gents,

I just figured out that redirect_to do something with the HTTP headers.
Specially the Content-type and charset.

I mean:

I got diferent encodings (charsets) if I use
http://myapp.com/welcome/index or http://myapp.com/welcome/

Can anyone tell me how can I solve that?

[]s

Manoel L.