[tlinux-users:08249] shift the keyboard to "PgDn"/"PgUp"

Hi, I am not familiar with the Japanese system of Keyboard, currently unfortunately, I have to use the laptop of such a system, does any one could be kind enough to tell the way how I can use the "PgDn"/"PdUp" key which are overlapped on the same key of the arrows? I am using Dynabook series

Thanks
EGao