Physically install your WLAN card first. Use lspci (get pci.ids as described here to convert those PCI numbers into more comprehensible text) and make sure your card is detected and is of the 'type' that you expect.
Make sure that the driver for your card is included with the addon or get it from some other source. If you do not have a driver, use google, search the IPCop support forums, etc. Do not Email me when looking for a driver.

Add a Blue Interface, open a console connection and type setup, change the network configuration type to include Blue:



First assign Red and Orange (if installed) normally. I repeat, install Red and Orange first and Blue last!
The Blue card will most likely not be found automatically, so do not probe but choose select:

Following step differs depending on your WLAN card!

If you have MadWifi or rt2500 Go into Manual Assignment and scroll down to find the Dummy Network Card:



If you have prism54 you select *MANUAL* and enter prism54:



Assign the card to Blue:



Finally set IP configuration for Blue: