Hi Mahesh, I'm not too sure. If you have pre-existing stylesheets you wanted to use I would try putting them through CSSjanus first, and then working with the converted stylesheets in CSS Modules. I'm not sure CSS Modules needs to know that CSSjanus even exists, or that the converted stylesheets it sees weren't the original ones you started with.
Do you have a demo, or any code online for how your setup is working? I'm not sure if I can help but there might be others here who might have ideas based on seeing what you're working with!