WepKC changes the WEP key on Windows XP SP2 by creating a XML wireless profile and invoking SetupSNK.exe, which is part of the new Windows Wireless Network Setup Wizard.
This *is REALLY* a stupid way of doing things and will be changed soon, at least in our plans.
The problem is that we're not used to programming in Windows and so we don't know how to accomplish this task so that it works for every wireless network card.

Notes for developers

We tried both WMI and DeviceIoControl() with no success.
Maybe we forgot something, any hints?

Creating a profile with the Wireless Network Setup Wizard

The Wireless Network Setup Wizard steps you through the configuration of wireless network settings and then writes that configuration as a set of Extensible Markup Language (XML) files on an Universal Serial Bus (USB) flash drive (UFD) or on an empty hard disk.

We took these information from http://www.microsoft.com/technet/community/columns/cableguy/cg0604.mspx, a very nice site that illustrates in a simple and effective manner (even using some screenshot) how to create the required profile. You are encouraged to visit that site and follow the steps described in the "Using the Wireless Network Setup Wizard to Configure a Wireless Network" paragraph.

Once the Wizard has written all the required files on the drive, you should copy the \Smrtntky\ directory and the Setupsnk.exe file to your hard disk so that WepKC can always access them. The Smrtntky directory MUST be placed on the FIRST LEVEL of the filesystem, for example C:\Smrtntky\ or D:\Smrtntky\. For instance, C:\foo\Smrtntky\ and D:\BaR\Smrtntky\ WILL NOT WORK !!!

Italians may refer to this page