The problem with using an internal redirect to some page instead of a browser redirect is that relative URLs will be interpreted wrongly - the browser is unaware of the real location of the page. So if you do an internal redirect to some-package/index from the acs-subsite index, and some-package/index contains a link to some-package/one?id=111, following that link will cause the browser to request the page 'one?id=111' from the acs-subsite package. Which doesn't exist.
I think the result of this is that a simple internal redirect (to a page) won't do the trick, and some clever use of a VUH is required. I guess you _could_ have an index.vuh in acs-subsite to handle the internal redirects to some other package, but as VUH's are last in the request processor pecking order, any pages still in acs-subsite's www directory would take precedence.
