I don't think there would be a problem with this as you can direct link to the sales pages with domain redirects, but by doing it that way you lose the chance of capturing the lead. Of course, you would (or should) need to host the images etc on your own server instead of hotlinking to the sales page as well.
What do you think? Would this be allowable? Because this way you are still utilizing a page known to convert, you are in control of the site and you are capturing the leads, plus skipping sending them to a repeated page (the publishers.)