Okay, so I did not hear from you on the veterinary side of things, was urinalysis done, if so, what did it indicate if anything at all, were any treatments administered for lower urinary tract disease, etc. Nonetheless, I will proceed with my answer as best I can in the interests of getting you an answer at least somewhat timely.

If a urinalysis has not been performed, that would be my first suggestion. Lower urinary tract disease (infection, crystals, stones, abnormalities in pH, etc.) is a common cause for litter box avoidance. Essentially, cats afflicted with chronic urinary tract disease commonly associate the litter box with the pain they feel while urinating...for that is the first place they felt the stinging sensation. In their minds, being in the litter box period may have been a contributing factor. As such, lower urinary tract disease MUST be ruled out before assuming that litter box avoidance and inappropriate urinating may be behavioral.

In event that has all been ruled out and Willie has a healthy, happy urinary tract, then pheromones would be my next try. I see in your post that you have already gone there, so my suggestion in that regard would be to use a trusted brand if you have not already. I like Feliway for behavioral voiding in cats:

http://www.1800petmeds.com/Comfort+Zone+For+Cats-prod10776.html
If this is to no avail, then I would suggest discussing with your veterinarian, dosing your kitty with amitriptylline, as tricyclic anti-depressant commonly used in feline behavioral medicine. It if often effective and very safe for use in cats...and with a generic prescription, it is also quite inexpensive. It does not work overnight, however, and may take several days to weeks before you see an improvement.