For a project I have to themes, say "A" and "B". Both based on the shipped tutorial theme files.
In the cms backend I clicked on the page root node and chose "A" from the theme dropdown menu (available are "default", "A", "B").
Creating a new page and open the preview works fine. My self created theme "A" will be used.

Now I have a self implemented static publisher which submits my pages to a external source. In the config file I set the following:
staticPublisher::set_static_publisher_theme('B');
Unfortunately this won't work. The pages will always rendered with theme "A" and submitted.

Choosing "B" in backend works fine. I assume this means that the Themes working right.

Any ideas?