applying theme to a module

I have applied a theme to my web application by declaring it in the /protected/config/main.php file.

I have added two modules, one created through gii tool and the other installed for shopping cart feature.

This theme is applying to the module that I created through gii tool, but it is not applying to the installed module.

How can I apply this same theme to the installed module?

There should be a config file in the root folder for the module. Check if a different theme is configured, or just try to enable your theme there if not :)

There is no such file or folder there inside the root folder of the module. The only folders/files present there are assets/,components/,controllers/,docs/,images/,messages/,models/,views/ and shopmodule.php.

If I create a config file for this module then what should be its name,and in which folder should it be placed and what would be its format? would its format be the same as the protected/config/main.php ?