Here is a sample XKeyboard Definition to include inside the Keyboard Section of your XF86Config File.
Xkbkeycodes "xfree86" /* XkbSymbols "us(pc101)+de_nodead" */ /* This has changed between 3.1.2E and 3.1.2F */ /* it is now: */ XkbSymbols "us(pc102)+de(nodeadkeys)" XkbTypes "default" XkbCompat "default" XkbGeometry "pc"
or you could use this one with the new Options:
XkbRules "xfree86" XkbModel "pc102" XkbLayout "de" XkbVariant "nodeadkeys"