I'll try to figure out how to register my Diamond version and my new DS together first -- I'm wondering if I might have to go through the Start Menu wifi-Configuration option again... I didn't try that. If it doesn't work then tomorrow morning I'll try to connect to wifi through my HeartGold version on my old DS, maybe the wifi was just being finnicky today. If that doesn't work either it would be great if you could transfer the Pokemon to Gen V when you're able, and we could make the trade on the weekend. ^_^'' No rush or anything.
Sorry for the complications. If I can just get my old game connected to my new DS with its perfect wifi access then trading should be a breeze in the future. X'D