outbound rewrite rule for ssl in parent page

i've got an outbound rewrite rule that changes urls on my page from their local directory to a cdn. so for example, it takes a image like '/images/myimage.jpg' and rewrites it to 'http://mycdn.com/images/myimage.jpg'.

of course, when that parent page is ssl, it needs to rewrite the link using https, not http. in my example: https://mycdn.com/images/myimage.jpg.

does anyone know how to do this?

it seems the outbound rule set only applies to the link itself, not to the overall url of the page.

if i were not to rewrite the link to https on an https page, the browser is going to give a warning and say that some links on the page are not SSL, and this is not desired.

thanks for any help!