How to boot to ClockworkMod recovery with Galaxy5 GT-i5500

I have ClockworkMod recovery installed on a phone (Samsung Galaxy5 GT-i5500, I have used it in the past to flash ROMs). The phone is currently not booting, just shows the Samsung logo. I want to get into the ClockworkMod recovery mode, by pressing some key combination. (Do not confuse with Samsung download mode: power-down+middle-button+power.) How to get to CWM recovery mode?