I'm using the Assistant to try to add a USB modem to my network settings. However, the option for "i use a telephone modem to dial my ISP" can't be selected. (please see attached screen grab) I've tried this under Tiger (10.4), Leopard (10.5) and, Snow Leopard (10.6). No luck in any of the last three MacOS's. Any advice or help, please? Thanks.