How to create a new module?

[dyaku]

Hi, 
I am using lyx for 2 or 3 years now and would like to customize it. I often
use the mdframed package and have to insert latex code each time I want to
use a defined environment. I would like to create a new module so I can find
these environments in the scrolling menu. 
How should I proceed?
Thanks,
dyaku