Bootcamp does not offer to change the scrolling speed of the trackpad in windows(as you have already seen) ..for changing the scrolling speed you will have to change the scrolling speed setting for mouse in the windows control panel.
you go to the control panel -> then go to mouse -> then go to "wheel" tab -> and set the 'no. of lines option' according to your convenience (1 works for me)....
but the problem comes when you are using an external mouse as well and this scroll setting turns out to be slow for the ext mouse.Windows does not provide separate settings for trackpad and mouse in the control panel as mac does..
but there are some applications that can be used to solve that problem....you can check that out at:
and one more problem that you'll find is that the scrolling direction of windows is not configurable and is opposite of that of mac...and that too can be solved....
Inverting direction of mouse scroll wheel
see if that helps