"previous slide" with automatic advance

When an timed automatic advance is set for a slide in an impress slideshow, “page down” overrides the automatic time, but “page up” does not. In other words I can advance the slide manually, but not move to the previous slide. It is not possible to “reverse” the slideshow from a timed slide other than by “alt-page up”. When using a remote ‘clicker’, alt-page up is not available. Can I do anything about this?