getting keypad +/- on Happy Hacking Kbd Lite 2

[Shimpei Yamashita <shimpei@example.com>]

I just got a Happy Hacking Keyboard Lite 2 (basically HHKLite+arrow keys),
and I'm having trouble getting it to generate keypad + / keypad - events
so that I can switch resolutions in XFree86. Since the keyboard doesn't
have any key combination mapped to it to begin with, I tried using
xmodmap to map the "Windows" keys to the two keys:

keycode 0x73 = KP_Add
keycode 0x74 = KP_Subtract

But no dice. xev shows that the keys did get mapped, and I can resize
rxvt using them (alt-kp+/-), but the X server ignores my ctrl-alt-+
supplications. Does XFree86 even pay attention to xmodmap for these
events? I'm wondering if I have to play with the kernel keymaps, or
(horrors) even recompile the X server to accept different key
combinations.

I know I'm not the first Happy Hacking Keyboard user in TLUG. Can anyone
help me?

-- 
Shimpei Yamashita                               http://www.shimpei.org/