Any USB keyboard with a scroll lock button should work perfectly, Apple's keyboards don't have a scroll lock button because, for most people, it's useless. You've already got page up/down and the scroll wheel on most mice, why have an extra button that no-body understands?
It seems very strange to me that a printer driver would take over the scroll lock button, does this mean you can no-longer use the button for it's original purpose?
Anyway, the answer is you'll need to plug in a keyboard with a scroll lock button, unless there's some software that will let you bind another key to scroll lock.