emacs 下无法呼唤 scim 输入汉字，请教！

exaos

我已经 global-unset-key C-SPC 了，但是仍然无法按 Ctrl-Space 呼唤出 Scim 输入法。很郁闷！
版本：
scim 1.0.1
emacs 21.3.50.2-cvs
gtk+ 2.4.14
系统：gentoo 2004.3 (2.6.10)
locale 环境：
LANG=zh_CN.UTF-8
LC_CTYPE="zh_CN.UTF-8"
LC_NUMERIC="zh_CN.UTF-8"
LC_TIME="zh_CN.UTF-8"
LC_COLLATE="zh_CN.UTF-8"
LC_MONETARY="zh_CN.UTF-8"
LC_MESSAGES="zh_CN.UTF-8"
LC_PAPER="zh_CN.UTF-8"
LC_NAME="zh_CN.UTF-8"
LC_ADDRESS="zh_CN.UTF-8"
LC_TELEPHONE="zh_CN.UTF-8"
LC_MEASUREMENT="zh_CN.UTF-8"
LC_IDENTIFICATION="zh_CN.UTF-8"
LC_ALL=