This has been address in the FAQ:
"Q. When tracing line of sight to the corner of a space containing a figure, does the figure occupying the target space block line of sight?
A. Yes, if the line passes through any blocked space (a space containing a figure or obstacle) the target space is not in line of sight. This includes the target space itself."
So apparently if you are targeting a figure in a given space, and the only way to get LOS to him is to trace to a corner of his space that the figure blocks, you don't have LOS.
I personally feel they made a mistake on this one. It makes absolutely no sense that a figure can block LOS to itself. If I can't shoot an arrow at you, because you are in between me and you, and the arrow would end up hitting you before it got to you, well that's just dumb! It's so dumb, it's hard to even explain how dumb it is.