I'm looking to have random explosion effects take place in mid-air. Sort of like the Kashyyk explosions that randomly go off on different places on the beach. How would I go about applying that same concept except so that the explosions randomly go off in mid-air?

The Kashyyyk explosions aren't random, they're just objcts with explosion effects attached. So you could take those explosion objects and place them all over the sky, but that would be fairly time consuming. The only other option I can think of would be using explosion effects that are used in the sky file in Geonosis, and simply having those going off in the background.

Oh yeah, I already added that. The problem was that I actually needed the explosions right in the battle. I'm thinking I might make a single effect with multiple explosions over a wide area and then add a few of these Kashyyk explosion object things. What's the ODF name?

I did this in Serenity Valley. There's an explosion in the Geo assets, btu I don't know the name because I don't have the mod tools on me right now. Regardless of name, you place the ODF in the map and random explosions will occur.

Train
I am not sure if you have found you solution to this yet but... Alpha was on the right track, there is something in geonosis that will work. It is a dome model called geo_sky_explosions.msh. Have a look at the geo1.sky file as to how it is set up add those lines to your .sky file copy over the required assets. There are some in the world1 folder and the rest are in the Effects folder. Since it uses a msh file you can scale it with an .option file which would effectively make the dome smaller bringing the explosions closer to the ground. Plus if you make a copy of the geo_sky_explosions.msh file and rename it to something like geo_sky_explosions2.msh
you can set up a second instance of explosions (just copy and paste the domemodel section and put in the new msh name also by varying the rotation speed you can make them look more random. The effect file they use does have random laser blasts shooting all over the place but if you don't want those there may be another explosion effect file you can put in instead. Also I do believe you can have a sound effect associated with the explosions as well although the effect file used doesn't have any.

I've already added that effect but I wanted the explosions actually in the battle[/b] not just in the background. If you watch BOC on youtube or on DVD, you will see explosions going off all over the place in mid-air (green and red) some of them really close to the screen.

What I'm going to do is use the kas_explosion.fx or whatever it was and then reproduce the explosion in PE multiple times and offset it so that there are like 10 different explosions going off in one FX file. That way, I can attatch it to one object and that one object (kas_prop_dirt) will cover a wider area with explosions instead of just putting the kas_prop_dirt all over the map.

This can actually be achieved with a custom model and some odf work.

Just make a large rectangle, make it invisible with no collision, place a bunch of hardpoints then attach explosions to the hardpoints via odf.

Easy enough to do and will take only 10- 20 minutes in XSI and notepad together.

Theres objects for this already, in the kas and geo assets. Posted above.

the geo ones name is geo_prop_splash.odf/.msh

Has 5 HPs in it, explosions are .fx place them around your map and watch them go off, don't place to many though because it can use up memory fast if you have to many