y'know, I just saw that same thread about the resolution. I did try changing it, and voila! Success!
About using FCDB to import kits, as long as you keep hitting next, no matter what options you've picked (Final Visualization, Modify Kit), you'll get to a "Last Step" screen. There you'll have a choice of either importing the kit into kits.big or copying the kit into the fifa directory (leaving kits.big alone). Any .fsh files in the root fifa directory are supposed to override other .fsh files found in the .big files, but I personally have never had good luck with this. Does this help, or am I just repeating myself and not answering your question?
Now, about the XGK kits, I've had good success with one slight addition to the above instructions: On the "Kit Creation or Modification" screen (the one that shows the files inside the .fsh), you'll see a drop-down box of predefined types (it's in french, "Type predefini"). Select the "32 bits (Fifa2002, WC2002)" option and press the Apply button. This will correct any .fsh files to make them compatible with plain ol' WC2002. I just triedc this with an XGK England kit, and it worked fine. Hopefully, this will hold true for you too.
If this doesn't make sense, let me know and maybe I can even do some screen shots...