I notice from their website that Stop Motion doesn't integrate directly with Pentax. But they do say:
Quote: If your camera does not have remote capture software, you may be able to use the
Eye-Fi card to transfer images to your computer, and then use folder watching mode in Dragon Stop Motion.
That seems a pretty easy solution to using the software to do what you want. Other people on this forum have used the Eye-Fi card with the K-x with success, so it should work for you.
Unless I am totally wrong about what stop-motion means, you could also go a simpler route and just use software to just blend a series of static images you've placed in a folder into an animation, like people do when they do time-lapse photography. It's the same thing as stop-motion, practically. Lots of graphics and video programs allow you to do that.