dead keys

I am sending WM_KEYDOWN messages from one window to another. This works OK
in English. In e.g. French, with the target window using a French keyboard,
I can use VkKeyScanEx to find out what key to send for most characters, like
for 'ç', wParam is VK_9. But VkKeyScanEx is useless for characters that are
entered using a dead key, like 'â' is the sequence wParam = VK_OEM_6 (a dead
key) followed by wParam = VK_A.

Is there some other function that will tell me how to convert a character
into the proper dead key sequence for a given keyboard?

Thanks,
Bob