When you're not a young lad any more, you will learn that the "whatever is the least pain in the arris" option, always has some merit..
Therefore.. why not do it "analogue"?:
When I fitted some LEDs to my Stilo, I picked up a feed from the dashboard fuse-box and ran it (via a fuse holder) to an illuminated switch I put in using the ashtray blanking plate .
It looks quite nice, I have to say.. but wherever you decide to put your switch, first make sure there is some space behind it, for the body of the switch and the wiring.
Anyway.. the switch was earthed using the nearby cigarette lighter socket (yes, Stilo has a cigarette lighter but you could delete the ashtray...
) and then the feed from the switch went out to the LEDs, which were earthed on the battery or car body.
The LEDs work on the switch. They're connected to the redundant sunroof fuse, which gives you 10-15 seconds of power after the ignition has been turned off... then cuts out.
I don't need LEDs when high beam is on (WTAF for?) and neither do you probably.. That sounds like the trickiest part of what you're trying to do.. and I can't understand what the purpose would be. If you have lights on, the LEDs should be off.
Ralf S.