ability to specify the protocol on sitemap items

It should be possible to configure for some urls (forms for example) that they should be secured using ssl.

This should be on a sitemap item basis, so some links have https as the scheme, but clicking another link should take me back to http.

If sitemap items are commonly shared between multiple subsites (are they?), it would be nice to specify per host if ssl is supported at all, if not the above setting would be ignored.