cant update header in a hosted Wordpress

I do not have my own WP installation and not planning to do so, instead I got an account with one of the zillion WP hosted services which happened to offer also your great theme. After tinkering with other settings I came to the point of uploading my own header picture.

Well, it's not showing up, and quite understandably so, because from the help page of the theme setting section I understand the headers must reside in image/header and obviously the post editing mechanism you suggested there is NOT uploading them in image/header (why would it) but into
/files/2009/08/atahualpa_header_1.jpg

Do you have any workaround how to get it, or am I really stuck? Once again, I'm asking this from the user point of view - no PHP access, no DB, no moving files around, as simple as that: can I do it through Atahualpa settings GUI?

Thanks a lot,
M