extjs minification using jsb2 builder

I am using JS builder to minify my extjs 4.1.3 JS and CSS files and my files are converting into minified file with name which i have given in .jsb2 file script. The name is statically mentioned in .jsb2 file. i want to generate the name of minified file dynamically with unique versioning through coding inside .jsb2 file.

And then I am referring that minified file name in my .txt file to run.

Now, I have to add some kind of versioning in minified file name to solve cache problem.

please let me know how I can add dynamic versioning like unique value in minified filename in .jsb2 file script.

is there any solution that we can do some javascript coding in .jsb2 file script?

I am using jsbuilder because my ext js code is not organised.