Hi,
you should have a look to the Launchpad S Programmer Reference Manuel [1] which explain everything you should be know to light up a LED on the controler.
The seection Computer-to-Launchpad LED Messages on page 12 describe how to do that.
You just need a [noteout] on channel 1 with the pitch corresponding to the pad number and the velocity codes the colour.
velocity = 12 + RED + 16*GREEN
With red and green between 0 and 3 I guess.
I made a little patch to use it's sister controler Novation Launch Control XL, attached to this email.
Yours is not the same, but it could be a stating point.
One thing in my patch you don't need I think, is that Launch Control XL has 16 layers on on each MIDI channel.
Then to light UP the LED on layer 5 I have to send note on chanel 5.
Cheers
Antoine