Switch Speed of Flash Video

I have two versions of a video. One is a normal speed flv video. The other video is 1.5X faster and is also a flv file. What I need you to do, is create a button at the bottom of the video that when clicked switches from the the normal speed video to the 1.5X video, but leaves the user at the same place in the video. However some calculation needs to be done because 150 seconds into video 1 would be only 100 seconds in video 1.5 for example since they were produced at different speeds, yet the same video. Additionally there is code that currently shows a form for the user to fill out that appears beneath the video at 777 seconds into the video. The time it shows would be different depending on which video they are watching. Let me know if you have any questions about this project. Thanks!