Question Changing the nether sky

So this Minecraft server i've been developing with a friend of mine is starting to feature a very intricate Minecart network in the nether, supported in the overworld by nether portals linking to Minecart stations.

As our nether area has developed, the surface of the nether has become really developed and I've been trying to find out how to add a sky to the nether beyond the default blood red. Searching for it on Google has given me ambiguous or hard to understand results, and I was wondering if anyone in this forum could help out?

Using Bukkit 1.7.9