Hi antkan,
It probably depends from your provider. For example, it doesn't work with mine, because it seems that there is a routing stage between the outside world and me. In other words several mobile users share the same ip address, similarly to what happens in a home with a router linking a home network with the outside. But the difference is that when you have a router at home, you can set forwarding rules to say that all incoming traffic on, say, port 80 gets directed to this particular computer (your webserver). However you cannot do that for your mobile terminal, because you don't have access to the router.
It might depend from provider to provider. At least for my provider, mobile user cannot be directly accessed from the outside.
Sam