This one was driving me mad for some time. Not sure why but I have a proper mental block over it. Anyway I found a solution.

Then problem:

You have and array of MovieClips that you want to add to the stage but you only want to display at any one time as many MovieClip as will physically fit within the boundary of your movie. For example, Your height limit is 400px and the first MovieClip is also 400px. Thus subsequent movies are forced into another “page.” MovieClip 2 and MovieClip 3 are both 150px high so that can both fit on page 2 and so on and so on.

Frameworks are great for producing RIA’s quickly but sometimes their overuse can result in over inflated file sizes, a poor user experience and an overloaded server. When file size is the most important factor you may consider building an ActionScript 3 project. However, this option creates a problem straight from off the bat., How do you pre-load an AS3 only project?