He's a shaman, planeswalking is in the job description. He lives on both planes, swapping back and forth numerous times a day. Hell, damn near the only thing keeping him on the physical plane is Irrelai. He can move from one to the other with barely a thought by now, since he's been doing it since he was a little kid. That kind of familiarity, while not really a specialty, would, I'd think, be reason enough for him to know about the possibility of creating a 'pocket plane.' To be honest, I'd think just about anyone versed in planes-walking would know about that. I also think it'd be a lot more difficult than you made it seem.
Gaserlake, how can I stick true to my character's knowledge when he would know something that I OOC am completely unaware of? And as for your linking crap, isn't that little more than a widespread telepathic network with a custom-made plane as a sort of connection hub? If so, then any multi-person telepathic conversation would utilize mind signatures as well, since they'd essentially be a local-only variant of your linking system, isn't that right? They'd act as a sort of telepathic variant of an IP address, from the way you've described your link. And just saying 'because I said so' is never an acceptable answer no matter what the question is. It's vague, certainly not an actual reason, and has never been accepted on the board before no matter what the context was. So why should we treat you any different?
Every friggen post I make it seems like my characters know more than I do about SP, which is quite the problem, as I'm sure both of you would agree with.