Changing the input method in Seamonkey to the X input
method.

I sometimes want to enter the "½" character and other iso-8859-1
characters in Seamonkey, but the "½" character doesn't seem to be
available using Seamonkey's default input method, so I want to change
the input method to the X input method. The X input method lets me do
<Compose>-1-2 to enter the "½" character.

But I don't know how to change the input method used by Seamonkey. How
do I do it?

I know that I can insert a "½" by doing these steps: (1) opening the
web
page composer, (2) seleting Insert/Characters&Symbols, (3) selecting the
½ character from the option-box, and (4) clicking the "Insert"
button.

That's like going from Boston to New York via Beijing. I want to get
<Compose>-1-2 working by changing the input method to X (XIM?). Can
someone help me?

Alternatively, can someone tell me where I find the list of Compose
characters for Seamonkey in iso-8859-1 mode?

Here's the software I'm using:
Seamonkey 1.0.1
XFree86 4.3.0.1
GTK and GDK 2.0 ?
Linux 2.4.27
Debian 3.1.