Ikelite housing and Canon 500d?

a friend of mine is looking to get the cannon 500d and ike housing but heard that with the 500d in manual mode you have to press a button next to the mode button while turning the dial next to the shutter, to do this with a housing would be a real pain a friend with the cannon 400d says he has the same setup and that he has some kind of lever that keeps the button depressed so you can adjust the shutter with the one finger,has the 500d have this setup,my friend wants the 500d but not if he has to change the setting with one hand while holding the housing with the other,i have the cannon 40d which has a better adjustment setup.any info would be appreciated
Steve

Our housing #6871.50 for the 450D and 500D also offers the same type of stay-depressed control for the aperture/flash compensation pushbutton. Thus you can engage the pushbutton and then rotate the dial control with one hand.

Regards,
Jean / Ikelite
IKELITE Underwater Systems