Animated gi lights in v-ray without using brute force

Hi there!
My site is almost up, and i´m in vacancies at the time!
Its as been quite a rush in the 2 last weeks, a job as entered the company and i had to struggle
to the end to make it complete at the end.
Soon i will publish a tutorial making the effects seen on that video.
For now i will try to explain one think that every one thinks it cant be done without having flickers in the images, a animated light with v-ray render engine.
Its can of basic but it only takes 2 steps to make it happen.
First use irradience map for first bounce and light cache for the second.
Your light should be the overall color of the light in the animation and should not move, in my case i changed the color the light throw time, so i choose white and render my light calculation.
OK. With my light calculation saved i select load from file and assign then.
Change the light to anything you want and give it its movement.
Render it.

OK , its not accurate, its does not look as good as with brute force, the the time you save could make you think 2 times!

Check out the video below.