No idea, didn't realise the calendar would have trouble with it. I suppose you'll just have to advertise manually, either way, an invite alone doesn't say much, despite the event description. Address people directly, and they'll be way more positively inclined to make an effort to showing up there
I think the way to add cross realm people is to write the name as it appears when you scroll over them, stutter-theshatar or something like that... had the same issue with mail.
Mind you, the example i did isn't exact, check in game how the shatar people are shown
Lilandris wrote:Liandrix' words not mine, but Tormeron is a god apparently. Probably a bit like Loki.