The only time i had the problem of gnome not showing up in xwmconfog was when i tried dropline. For some reason it didn't put i file in /etc/X11/xinit/
Pretty easy to fix though create the file /etc/X11/xinit/xinitrc.gnome
in that file put this;
# $XConsortium: xinitrc.cpp,v 1.4 91/08/22 11:41:34 rws Exp $
# merge in defaults and keymaps
if [ -f $sysresources ]; then
xrdb -merge $sysresources
if [ -f $sysmodmap ]; then
if [ -f $userresources ]; then
xrdb -merge $userresources
if [ -f $usermodmap ]; then
# This nag screen isn't going to save anybody.
# Start the window manager:
you'll have to be root. After you create and save the file make it executable chmod +x xinitrc.gnome
should be good to go after that.