Fixing backend URLs

[Chris Cook]

I have an application that takes a URI that's submitted and spits back
a different URI with a 302 redirect.  The backend server translates
this and sends back a new URI that contains the backend server port.
I want to use Varnish to remove the backend server port before sending
the request to the client.

Varnish receives - http://domain.com:8080/blah/stuff
Varnish makes it - http://domain.com/blah/stuff

What's the best way to do this?  I assume it involves vcl_fetch and
some variants of the beresp, but I haven't been able to figure it out
yet.

Thanks!
Chris