Collectible Card Game Headquarters

I want to change a few cards for a deck because I'm a cheat like that.. How would I go about editing a card for example like from 4WW to... let's say 3BU?

I've tried changing the file extension from .mwBase to .txt, .exe, .doxc, .pdf, and .xls... and nothing worked Suggestions please?

w00t first post ftw

*EDIT* Neveeeeeeeeer mind! I found in tools > card creation center > then I just added the picture to it win!