Changing registration point dynamically

hello,
the great sripter
need a help

I want to chage registration point of movie dynamically. Images will come from the database.
It is basically a slideshow for realestate.
User can adjust the registration point of the movie, from that point the movie will zoom In or zoom Out. see the existing example.
http://www.realestateshows.com/show.php?id=1965
or
http://www.realestateshows.com/index.php (then click on example link)

how can I achieve this task from AS

Regards,
Amol