If you need Flash Exposure Compensation in camera along with WB adjustment, there is new firmware hack from Wasia.

1) You have to download file named E3kr111setfec.rar from http://satinfo.narod.ru/
2) unpack it
3) install new firmware into your camera (read http://web.canon.jp/Imaging/eosdigital/E3kr_firmware-e.html for instructions)
4) go to custom functions menu (unlocked) and assign FEC adjustment to SET button.

From now on you can trigger FEC adjustment menu by pressing SET button in record mode. ADjustment is made by turning wheel in steps of 1/3 from -2 to 2. It is saved when turning your camera off. Also it will be stored in every image info.

Read custom functions description at http://www.bahneman.com/liem/photos/tricks/digital-rebel-tricks.html

Read about previos firmware hack at http://forums.dpreview.com/forums/read.asp?forum=1031&message=8246765

Notes: Red Eye will start blinking as soon as you change anything in custom function menu. (Use previous hack if youi hate Red Eye).

PS If you really want to support Wasia - send few dollars/euro to PayPal account dap78@online.fr. I will try to pass em to Wasia, probably converted to beer currency.