TCP/IP devices don't inherently have hostnames. The normal way to give a hostname to a TCP/IP device is via DNS, but most people aren't running local DNS servers for hosts on their internal network. If you have something that is showing "names" of devices on your network, it's probably picking up the SMB/NMB (NetBIOS) name, which is a Windows thing.

If that's the case, you might be able to accomplish this using one of the SMB tools mentioned in the Captivate FAQ (see the wifi section): Connectivity - CapFAQ

I have not tested this though.