Hit the alt button when selecting wireless encryption mode and the option for WEP should come up on the wireless creation menu, from several call to apple I found this out, only unfortunatly it didnt work on my capsual
WEP will not appear unless you have a compatible Radio Mode selected. For example, WEP will not work on "n" wireless. There are a couple of settings for Radio Mode that will allow a WEP setting.
Hold down the option or alt key while you click on the Radio Mode selection box. It appears as if the three radio modes that might work with WEP are:
802.11a -- 802.11 b/g
802.11a -- 802.11b
802.11a -- 802.11g
Try the 802.11a -- 802.11 b/g setting. Now you will see that a WEP options appears
You also might experiment with WEP Transitional for some options.
Unfortunately, WEP is long out of date and there are dozens for free utilities available on the Internet that will crack a WEP network in a few seconds, so you might want to think about this before you try it.