All you need to do is piece your binding lengthways, cutting 2 strips of fabric ....
For a flange cut the fabric you want to see a 1/4" (I cut mine 1/2") wider than the second fabric
Join the WOF on the diagonals as you would a normal binding and then sew the two together lengthways.
Fold exactly in half and one side will have that strip of colour on.
You can work out which way to attach it for yourselves.
For a dual coloured binding (which I believe I invented, well in my head I did cos I googled and couldnt find anything like it )
For a 2 1/2" binding (the usual size) Cut one fabric 1" wide and the second 2" wide.
Proceed as above and press in half.
You will have one side all one colour and one side two colours but when attached you should have one side Red (for instance) and one side White.(FI)
Dual coloured binding tut