You're connecting the two wireless? 802.11a? b? g? n? Either way, it might just be the connection speed.
I know, even on a wired connection, it can take a bit before any of my computers show up on the network. It wont be immediate like a local hard drive would be... it does take a bit of time.
Might be more of a help if you give us an idea of how long you have to wait?