Haven't you installed the Office 12 beta?
That limitation is NO LONGER there !!!
Office12 is not a product that the average Office user can get hold of.
It's a beta.
A techincal beta.
A limited availability beta.
A beta that has problems in so many other areas it would be listed as a "worst product" in its own right if released to the public at large in its current form.
The product that real people in the real world have to use has the limitation that w3bbo pointed out.
Of course, whether that limitation really makes it one of the worst Microsoft products is a whole different kettle of fish.