Help with web gallery

hey People,

Ive been working on this xml photo gallery for weeks no, learning xml with flash is new to me, so it take me longer.

Ive almost got it the way i want, im just having a problem.

Say i have a grid of 5X5 thumbnails and when i click on one the large image shows up and i want it to show up OVER the thumbnails and then a button to unload that so it goes back to the thumbnails but also so i can keep navigating.

I cant get this to happen but im sure someone with more experience could help me out.

To explain easier i have attached the file.

Many thanks

kym