Selected Networked Workstation does not elicit any setup for networking when Custom is the selected mode.
User will only get prompted for networking information if a network device (NIC) is found by the installer.
The NIC installed is a 3Com 3c509 and the 6.0 installer found it OK.
Is this an ISA card? The 6.1 installer takes a less invasive approach to ISA probing, so if this is an ISA card, then you are probably going to need to run the installer in expert mode so that you can specify that you have this network card in your system.
Somehow that needs to be made clear in the install guide. Since I have used 5.2 and 6.0 my expectations were set. I took the intent of the new installation to be less input from the installer, ie. sysadmin, but it seems that 6.1 may require more than the recent releases.
We will document the change in the next release.
I just wanted to chime in with the news that this is different behavior than any RedHat installation prior at least to 4.2. I've been re-installing on the same set of systems for a class I teach, and 6.1 didn't spot the network cards, but the prior versions did. So, adding documentation for this to the installation guide would help.