Modifying bootkali

I have been working on creating some more apps for making the "click-hacking" portion of NH a little easier. However, I am running into an issue that is making it a bit more difficult than I expected. I know I have two choices in how I implement it - 1. modify the existing bootkali script OR 2. grab a portion of bootkali (top 80 lines or so -all the madatory lines) and paste them in my own script (e.g. mybootfile). The problem I am having is that bootkali is found at /system/bin/bootkali - when I try to edit it, I get a message that says that it is a "read only" file system and therefore changes fall flat. If I try option 2 and write my own, and put it somewhere else like the SDcard I can't make the script executable. So either way I am at a dead end. How do I go about mounting /system/bin/ so that it is RW? Or alternatively where can I place my shell so that it will be seen and executed?

I appreciate any feedback and tips - I promise it will be worth it to the community if I get this working as I am porting all my scripts from the PwnPad over point-click-hack can't get any easier than that.

Securemaryland