9900ix Sleeper Rear Lights

[TBraun]

I'd like to add a few lights to the back of the sleeper on a 9900ix. It has the 2 factory installed lights now. I'd like to add one out further on each side and one straight up from that one more to the top of the sleeper. Installing them should be no problem, and I'll pull power and ground from the 2 original lights. The problem I'm seeing is, How do I get the wiring through the structural supports that are in the back of the sleeper? The 2 extra lights that would be straight out from the original lights will be easy, it's just a straight shot out with the wires. But the ones up higher would be on the other side of 2 supports. I'm assuming the structural supports and some kind of square tubing or "I" channel that do not have holes in them. Anyone ever done this? I don't want to have to take the inside of the sleeper apart in order to drill holes in the supports. If I have to do that I'll ditch the idea all together. But I don't see any other way to do it. Any information would be appreciated. Thanks.