Seamless from one video to another.

I am trying to create a simple interactive where a video of clouds plays in a seamless loop. The user then pushes a button which plays movie number 2 which is thunderstorm near the end of the thunderstorm movie (inside the movie) it transitions back to clouds so that the final frame of the storm movie matches the first of the looping clouds movie. after the storm movie ends it goes back to clouds the seamless loop works fine and so does the push button playing the storm the problem i am having is the seamless transition from the end of the storm movie back into the clouds movie loop. every way i try to do this i get a slight freeze before the clouds play. Is there a trick to getting one move to play seamlessly into another? should i be using the 'Preload' command in the script somewhere? if so where should it be? I have been using bright author to create this (using Lyndon advice) I have the latest brightauthor, Firmware and am using HDMI on a 410. resolution will hopefully be 1280x800x60p if i can get that working (being discussed in another topic) but for this test i am using 1280x720x50p