It is indeed my lucky day! I can't thank you enough! exactly what I needed!
Thank you so much!

Just an note on what I tried with it last night. When you link track 2 to 1 and then go to the link and click on inverse you can make the coloured object appear in a totaly diffrent video on track 3. I managed to get a pair of red fire doors apear in a different clip, I also manged to get a differend clip to appear through the red doors, sort of the door to a different world, or the secret garden.

Another way that only requires two video tracks, is outlined in Douglas Spotted Eagle’s new book, "Vegas 4 Editing Workshop". Spot’s solution is to place the same video on two tracks. Add a chroma key and black & white effect to the upper track (in that order). Turn off the chroma key and black & white filter temporarily and select the color you want to remain from the chroma key tool. Turn the chroma key and black & white filters back on and you’re done!

The chroma key punches a hole in the upper black & white video to let the lower color show through. (essentially doing the same as compositing with the mask from the color correcting tool but with one less track) And that’s what's great about Vegas. It’s so rich in functionality that are often more than one way to accomplish something. Using the chroma key has the advantage that it also works in Vegas 3 and Screenblast MovieStudio too. Spot’s book is full of great little tips like this (as are Edward Troxel‘s newsletters), I highly recommend them both.

~jr

Jetdv just had a big article on how to do this in his tips and tricks newsletter.