I am using a different workflow:
I first extract .tiff images from the .pdf slideshow using the $59 PdfExtractTiff (http://www.verypdf.com/pdf2tif/).
You can then use your favorite tool to create your QuickTime Movie. I personally use Pictures2exe to create slideshows and Windows screen savers. It can only create .avi movies, but I am sure that a quick serach will find multiple programs that will create a QuickTime movie from series of still images.
A bit annoying that the original Adobe promise (LR 1.0 Beta video tutorials) to support multiple slideshow export format has never been fullfilled.