How do I load existing Memory-Map format maps onto my iPad for use with the app?

Any maps that you use with the Memory-Map desktop mapping products can be used on your iPad / iPhone.
This includes Memory-Map map packages, or any third party maps that are compatible with the desktop software. For example BSB charts, or eTopo maps can also be used.
You can also scan a paper map (with the permission of the copyright holder), calibrate it using the Memory-Map desktop app, and use the result for navigation on your iPad / iPhone. The map files (with QCT, QC3, MMI extensions) can be loaded directly off your original Memory-Map DVDs (providing the files are not bigger than 2GB).
Alternatively, they may be found in a folder on your PC (typically C:\Maps or C:\Maps_V5).
To copy the maps to your iPhone/iPad, sync it with iTunes using the USB cable. In iTunes, select the device, and click the Apps tab. At the bottom is a section that shows all the apps that support file sharing. Select Hema 4WD Maps. You can now drag-n-drop files and folders into the list on the right.
When you have finished copying files, you have to re-start the app. Press the home button to close the app, if it is running. Now double-click the home button. It displays all the apps that are running in the background. Find the HEMA 4WD Maps app (you can scroll sideways). Swipe away to terminate the app. Click the home button again, a couple of times to get back to the home screen.

When you re-start the app, it scans the files to re-build the list of maps.