I wonder is it is primarily a Mountain Lion / Airport Utility 6 issue.
If you load airport utility 5 it might work better.
How to load 5.6 into ML.
1. Download 5.6 for Lion.
Click to open the dmg but do not attempt to install the pkg.. it won't work anyway.
2. Download and install unpkg.
You might need to allow other downloads to work, as security is tighter in ML.. go to preferences and security and set it to allow. Or control click the icon for unpkg and it will request permission to open it.
Run unpkg on the desktop.. it is very simple.. drag the AirPortUtility56.pkg file over to unpkg.. and it will create a new directory of the same name on the desktop.. drill down.. applications utilities .. there lo and behold is Airport utility 5.6 .. drag it to your main utilities directory or just run it from current location.
You cannot uninstall 6.1 so don't try.. and you cannot or should not run them both at the same time.. so just ignore the toyland version.. the plastic hammer.. and start using 5.6.. a real tool.
For screen shots see this post.
Give us a couple of screen shots which show the issue.. this could be helpful to others.
Hey and thanks for the answer.
I tried the AirPortUtility 5.6 but that version seems to not show any names at all. (screenshot)
But anyway I'll keep it...amazing how many options were kicked out or tucked away in APU 6.1
Oh and today even a PC was shown by it's PC-name in the APU 6.1 (screenshot).
I am beginning to fear my Macbook has some strange setup, which blocks sending an IP and name.
Anyway in a Windows-Network the Laptop is listed by its NetBios-Name and when using IP scanners it's shown visible.
Starting APU I noticed the TC first showing the IPs of the clients and then after a few seconds the names are resolved