Please note that this is a really specific question about how to configure the application. This Community forum is intended to solve problems related to the Bitnami Stacks, Virtual Machine or Cloud Images.
For information regarding the application itself or customization of the content within the application, we highly recommend checking forums and user guides made available by the project behind the application.
I found this thread in the OpenCart's forums that might help you
As you already know, all the OpenCart's files are under