Shift+PgUp and Shift+PgDn should scroll the terminal, although sometimes you will need to have Scroll Lock turned on in order for them to work (I don't understand quite what these conditions/settings are).
Also, note that your scrollback information is held in video memory, so it can get zapped when you switch between virtual terminals. The only workarounds for this case are either not to switch VTs or to use the a different graphics card driver.
Do your PgUp and PgDn buttons work without shift (eg. to scrolll through your BASH history)? If not, then you have the wrong keyboard map installed for your keyboard, which could also cause this problem.
Hope that helps,
— Robert J. Lee