You can unlock the combat chat frame and drag it and resize it on to the kgPanel you've made for it.
I personally use
Chatter to manage chat frames but it does the same stuff as Prat.
kgPanels has a facility that allows you to make panels visible/invisible (or other stuff I suppose) on certain events occurring. That functionality is covered under the Scripts menu item and you will need a little lua (or a lot of lua) knowledge to get it running. You could try the
kgPanels forum on wowace as that kind of question has been asked there before. My minimal attempt at scripting kgPanels got it's inspiration from there.