Yes, you're right. When I wrote EasyTiler, only Google Earth exists (or at least I know only about it). I suppose it probably can be possible a similar program can be written for virtual earth, but some work and experiments will be needed, because i suppose storing of the data and calculating the coodrinates in virtual earth will be totally different from this in google earth. But it will be interesting.
Please send me your email, because i received your message later from my forum, but there was no back address and i cannot answer to you.
Best regards, NickD