You can now replace the standard license/splash page with your own by creating a program ATESPLASH.LIT and placing it in the ATE directory %MIAME%\custom. As long as the file exists, and ATE was not launched with the -n option, the program will be executed instead of the standard license/banner.
Note that unlike the built-in splash display, which lingers while internal operations are proceeding, ATE will simply wait for the ATESPLASH.LIT program to exit; so you should keep the duration of the display short, ideally only one or two seconds.
Also note that the program might be executed before the full runtime environment has been established, so the program should be kept simple, with no SBX calls. Any files that you need for the display, such as an image file, should also be stored in the %MIAME%\custom subdirectory.
See sample in SOSLIB [907,50].