but is possible create a script for this application?

Don't think you could do that with a script. Keyframing would achieve the same result as what you can do with AE, AE does much the same thing but it automates the task by tracking points to generate the keyframes.
So here's the thing, if you need to do this a lot then cough up the dough and buy AE. Not everyone needs these features so by NOT having it in Vegas those who don't need it aren't paying for it. I'm certain Adobe have the same reasoning when they didn't build it into Premier.

i am user vegas 5. I have already bought vegas.
This it is a suggestion for a plug-in.

Here is a cheaper alternative for motion tracking if thats all you need
http://patchmaker.net

There is also a free program that is in development, it is about 80% functionality.(can do zoom and pan tracking, but does not have tracking finished). i am still looking for the link, and will post it when i find it

here is the link to the free software. It looks like it mostly deals with match moving, looks verry promising for a lot of appliocations.

There are two realistic alternatives. If you've gotta work within Vegas, use Boris Red. It's got one of the best motion trackers known to man. If you don't mind working outside of Vegas, Dynapel's Steadyhand gets constant use by me.

If you only want to do stabilizing you could also use the VirtualDub Deshaker plugin. This one works great. Configuration is a bit complex but I like the results more than what SteadyHand outputs.

Marco

tracking point util not stabilize only the image, but util for move mask. if you copy keyframe in mask motiontrack, the mask moves