Only the sweaters built directly into CustomFit can be, well, made directly with CustomFit. My book patterns, and some other designs, aren't built into the site either for copyright reasons or because CustomFit isn't flexible enough for me to create the design in the site (yet).
But, I'm thrilled if you'd like to knit one of my other sweaters! You'll have to work a "mash up" of the traditional pattern with your CustomFit pattern - I've written an article about that process here.
For some of my designs, I've gone one step further and made a "mash-up worksheet" to help you through the process. You can download those for free on this page.