The attached file has backgrounds for the modified AlphaKeyboard in the previous post.
Extract the files, right-click the AdvancedHMIControls project, select Properties and in the Properties window select Resources, switch to Images, click Add Resource drop down and select Add Existing File. Browse to location where you extracted the files and select them all at once.
Rebuild the project (if necessary close the project, re-open it and then rebuild it).