Distinguish between left and right shift keys using RAWINPUT

Question

RAWINPUT provides two flags (RI_KEY_E0 and RI_KEY_E1) to check whether the left or right version of a key is pressed. This works great for CTRL, but not for left and right shift. In fact, the flags are the same for both, and the VKey is also the same (VK_SHIFT). How can I find out which shift was pressed? I'm working on Windows 7. Interestingly, the flags/vkey values are exactly the same no matter which shift key I'm pressing.