In firefox Alt+Arrows is for back/forward navigation.
]]><keybind key="A-Left">
<action name="Execute"><command>xte "key Home"</command></action>
</keybind>
<keybind key="A-Right">
<action name="Execute"><command>xte "key End"</command></action>
</keybind>
Which did the trick, although it doesn't work in firefox for some reason.
]]>xmodmap -e 'keycode 114 = Right NoSymbol End'
but it doesn't seem to work.
]]>