I can not say for 100% certainty, but I believe it is as simple as WoW will not recognize non-standard input passed into their code.
This is, unfortunately for multi-boxers and macro junkies, best practice when it comes to security. It's part of sanitizing input code.
I have tried many combination of non-standard characters and it simply would not take. Check out http://www.dual-boxing.com/wiki/inde...ld_of_Warcraft
for a complete list of what will work and the combination there in. Keep in mind some of the modifier combination will actually pass to WoW but they are defaulted in windows to functions that will intercept it before it gets to an application. If you disable the windows hotkeys you can use them. Or you can do what I will be doing when I get my DX1, Using the "deep key combos" of already bound keys, <ctrl><alt><shift> 1 through = for example.