This post describes how to add custom bundles to a ESXi image. In this example I'm adding PowerPath but the process applies for any other driver. First we need to load our base image into the image builder. 

We now also add your PowerPath bundle

In the next step we create a new image profile by cloning the existing standard base image.

Now we can add the PowerPath modules to our created image profile

The final task is now to export our image to a ISO to use it for installations.