My journey through InstaDMG

I'm completely new to all this InstaDMG and I've set a few goals for this project that I'm carrying out. I'm not the most Mac savy but I can read and get my way around using logic. So far, I managed to create a successful vanilla image by following the guide on the Google Code website. I can boot into that just fine. Today I wanted to test how to add regular applications that are simply dragged to the Applications folder (i.e FireFox). So I modified the 10.6_vanilla file and came up with the following: