While the suggestions are valid. The question being posed is can you call an external .html page into a Tourweaver Pop-Up window? Not a new browser window.
Much like you can call a Google map into a Pop-Up window people would like to call "any" .html of their choice into the same. Even if it is limited to "some" html tags and not all.
At least this is how I read the question being asked by Tomax. Basically a chromeless .html window with Flash.