The CV50 has a Japanese keyboard. An external keyboard can be attached to the USB port. I used a USB to mouse/keyboard converter (from Belkin). My Logitech Deluxe 104 keyboard (PS/2) works attached to the converter, my older Honeywell keyboard also needed a DIN5 to PS/2 adapter.
The Logitech and the Honeywell keyboards are US keyboards, rather than Japanese keyboards, and so have a different positions for keys like `apostrophe' and `bracket'. With KDE, you can add a US keyboard layout to the Japanese layout through the Control Centre under `Regional and Accessability -- Keyboard Layout'. On the left tab, tick the `enable keyboard layouts', if it is not already ticked. Then add the `U.S. English w/ ISO9995-3 (en_US)' layout, which should transfer that layout from the left side of the list to the right side of the list. The `U.S. English (us)' layout has a lot of deadkeys enabled, such as the apostrophe and tilde. Unless you want to hold the Right-Alt key down whenever you want to type an apostrophe, it is better to choose en_US. Make sure you also have a Japanese keyboard layout added to the right side of the list as well! You can swap between the en_US and jp layout with the `Ctrl-Alt-k' keyboard combination, or by using the tray applet in the KDE taskbar.
Unfortunately, there remains two problems. X does not generate a keycode when the `Win' (called `Super-L/R' in Linux) key is pressed when using the Japanese layout, at least with Xorg 6.8.x. KDE 3.4.x has also removed the ability of using the `Win' key to popup the Launch menu, because `Win' is defined as a modifier rather than a stand-alone key.