Hi Brian. A bit stunned and staggered mate... but thanks for asking... here we go... please bear in mind that I did this well over 6 years ago so the detail is just a tad fuzzy.
I think I used a 3 pin flasher unit and ran a wire from the 3rd pin (pilot) to the switch. The attached photo shows the small led I used. I purchased these from Jay Car... any electrical come hobby type place would stock them I guess. I think I bought 10 for $1. So if I made a few mistakes I was well covered.
I then attached one side to the pilot lead and the other to the left hand indicator lead, turned the switch on, if it worked, fine, if not I swapped the led "tails" round... I am no expert with electrical stuff... (Limiting myself to a particular confession here, hereby saving days of writing).
When I was happy that it worked, then I used the appropriate sized drill to make the holes, took a bit of clear sealastic to use as glue and seal and then had a ball trimming and soldering wires and tails to get em all to fit in the switch and not short each other out. By now you have correctly assumed that I did the same for the right hand indicator.
I wish I could be of more use to you. But roughly speaking it was as simple as that.
After 6 years of riding they still work really well. However I have found that I also rely on the front indicator itself to let me know if the indicator is on. These are the ones that have enough "Face" showing along the top so that i can see the top part as I ride.