Finally I made my patch.txt working. In my patch, I printed something when somebody clicks on "Compose" in Thunderbird.
Here is the file ...
It provided so much confident to me for working on my project. I am also excited as I got the project that I wanted !!! Somebody dropped that project and I could get it. Now, my project is switched to Thunderbird-Draft-Schedular from Weave. Thanx humph for providing me this project.