States in the software are identified by abbreviation (FL for Florida, for example). If you wish to create a new state you can do so, but you'll have to create your own abbreviation. You cannot overwrite any of the known states.
When you download the latest data from the web, only the standard states are updated. Any states that you have created are not affected by the download.
To add a new state, click the Add A State button. The Add New State window will appear, allowing you to copy an existing state and give it a new name and abbreviation.
Once you have created a new state, click on it in the Select State list and click Edit State. The Edit State button replaces the View State button whenever one of your states is selected in the list.