Hi,
I do not understand the problem. You were stating that the PC/skype setup is working fine. The setup look like this

headset-----[PC..Skype..]---wl500g--adsl----internet-----
[READ: headset or mic/PC-speakers]


But replacing the headset with

pstnphone/DECT-E-zi phone ---(usb)-[PC..Skype..]----wl500g---adsl----internet-----

From a network point of view, the set up is identical. My best bet is to look into the settings of skype. Skype must know which human input/output interfaces it should be using.

http://www.100mhz.nl/downloads/E-ZI%...r%20Manual.pdf

I hope that it will work... success