Define hot key to swap file displays

One of my commonly used features of DOPUS in the ability to swap left/right panes with the "Swap file displays" little button. How should I define pane swapping?
Many thanks.

That would be:

<?xml version="1.0"?> <button backcol="none" display="both" textcol="none"> <label>Go Swap</label> <tip>Go Swap</tip> <icon1>#split</icon1> <function type="normal"> <instruction>Go Swap</instruction> </function> </button>

Thanks abr, But as I have mentioned, there is a button defined in DOPUS. What I'm looking to accomplish here, is to define a new hotkey that does the same thing. By adding a hotkey in:
Settings => Customize => Keys => New Hotkey
I do not know what to put there to accomplish the same thing.

Urgh! I'm such a dumb!
Thanks abr. that Go Swap thing did the trick.

If you paste the code into a toolbar, you can afterwards edit it (Alt-click on it).
You can use the "hotkey" field in the command editor.