I remember you bringing this up on the IRC a while back, and I had mentioned thaere were e-Card test menus in the Debug Ruby rom. Perhaps doing some research into how that works may provide some insight into how that system works. If I can get my hands on a Pokemon Sapphire save and copy it to my retail card and get another Gameboy, I will test what kind of eCard it sends and see what it does on hardware.
If it doesn't work on hardware because of language limitations, I might have to get another GBA flashcard or import a German copy of RS. If worst comes to worst, I'll have to emulate.