Well, you had way too many abbreviations in your question for me to know if I'm helping you or not -- I THINK you're trying to connect a Windows machine to your wireless airport network. I had to do this for my husband's laptop recently.
You'll find the equivalent password in the airport configuration. Launch the airport administration utility, then click on configure -- look under the various headings (can't remember the name right now -- sorry) and you'll find the WEP equivalent.
I THINK this is what you need, but I'm not sure.
Also -- try the Apple discussion boards. That's where I found my help on this particular matter when I needed it.