you can buy a cheap uninsulated terminal screwdriver and bend the shaft by 90 degrees, then use another screwdriver as a pivoy point, but be careful as not to break the little latch that holds the button in place
For more info look at this great website
www.clayraku.fsnet.co.uk/index.html and click dyson dc04
it also covers clutch removal and how to strip the dc04 down
Graham (Dysonmania) groups.msn.com/dysonmania, April 2005