I'm doing PXE installations using preseed file for Ubuntu. I was able to configure the gnome desktop default for the system network manual proxy configuration for Fedora's kickstart file using gconftool-2 as shown below. Can I do something similar in Ubuntu preseed file?

gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=bool --set /system/gnome-vfs/use-http-proxy "TRUE"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=string --set /system/gnome-vfs/http-proxy-host "proxyxxx.name.com"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=int --set /system/gnome-vfs/http-proxy-port "XX"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=string --set /system/proxy/mode "manual"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=bool --set /system/http_proxy/use_same_proxy "TRUE"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=bool --set /system/http_proxy/use_http_proxy "TRUE"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=string --set /system/http_proxy/host "proxyxxx.name.com"
gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.default --type=int --set /system/http_proxy/port "XX"

Thanks