Discovered this helpful post:
Basically what you're running up against is IE's need for a "tbody"http://groups.google.com/group/mootools-users/msg/b453322628b35e52?pli=1
element when you create elements. It just won't put anything in the
table unless it's got one. I've done this on the JSFiddle I linked above.
Huh. Unbelievably, it worked.