nothing can connect to a 192.168.x.x from outside, think about it, no outside routers will pass on a packet to a 192.168 destination, and it looks like your box has gotten a ip assigned from dhcp from your setup cable modem/nat, this is good for your protection and push will have to be used I may be wrong, so you wont get as many files as if you had your own ip though
there should be no problem getting hosts to connect to, even with a 192.168 ip, once you get a few good ones to start with so I think that was your problem at first
if the nat box passes packets on to your ip and same port, that would seem to work right and forcing the ip would then work, monitor with tcpdump and post back this is interesting to see if it works this way