No problem. Our mast step plate has a weep hole on the leading edge for the purpose of allowing rain water, as it comes down the mast, to flow out rather than pooling up and over the coach roof conduit and into the main cabin. The wires that come down the mast, and before they enter the coach roof conduit, have a drip loop "U" before they enter the coach roof conduit. That way any rain water that flows down the wires will drip inside the mast step and out the weep hole and not follow the wires into the main cabin.
http://www.wirefacts.com/web/Images/Article122-0.png
Of course it easier said than done with the mast already stepped. Our drip loop was placed as the unstepped mast was being stepped. A different story when you want to install new wires and ensuring there is a drip loop in the wires with the mast already stepped.
I'm trying to think of a way, short of lifting the mast off the step plate high enough, to place a drip loop in your new wires. Here is a thought...after running the wires up to your new fixture, where the wires come through the coach roof conduit inside the boat, form the two wires into the shape of a "N" or a "W" and squeeze them together so that they will slide through the conduit and up into the inside of the mast. That should give you the drip loop that you need.
If I have any other silly ideas I will post them here.