DL Modding files:

DL CS5 Modding files:

Inside the zips you'll find SDTMod.fla, an ExampleMod.fla which recreates SD Chan's hair and the t-shirt, and a folder with some ActionScript files. SDTMod.fla is what you'll actually use to make your mod, you don't have to worry about any of the .as files. You only have to edit a few lines of code in the fla.

There is a short readme, and you can see the same tutorial with some more details in SDTMod.fla by opening the ActionScript window (Window / Actions) and clicking on the README and Settings layers.

Example dialogue mod source:
DL: InsecureDialogue.fla
DL: InsecureDialogue_CS5.fla