This site is being deprecated.
Please see the official X‑Plane Support page for help.
You can customize any plane that works in X-Plane with Plane Maker. Please check the license on the plane you have purchased to see if making your own adjustments is allowed or not.
There is a small section in the Plane Maker manual about setting up the GPS. There are also two articles on the developer site that might help: Old vs. new style GPS & Source Selectors.
I have only poked around in Plane Maker enough to know if our manual is completely wrong or not. ;) I don't have any experience creating aircraft, but I found this thread on the independently run X-Plane.org forum that might be helpful. I believe you can read it without being a member, but you will need to sign up to post any questions for help from the designers there.
This site is no longer being actively maintained.