In each race's player.entity file, which in turn probably references to the string file.

Holy cow--Stant liiiiives!  Hi guy!

How can i add a new ship to the game ?

For such a simple question it's actually quite a long and complex answer.  Distilled down to the basics, you need a mesh of the ship, you need textures for the ship, you need to add the infocard entries into the string file, you need to add it to a few places in the galaxy scenario def file to allow it to appear in the game, you need to add in the entity file for the ship so the game knows what it is and how it works as well as any entities needed for special abilities that you've given to it, you need to add in the effects for any custom abilities created, and finally, you need to add the ship to the player(race) file in the proper section for each faction that you plan on allowing to build it.  It's probably best to start off customizing an existing ship until you're familiar with the process.

Visit MyFist0's site http://soase.x90x.net/ for a much more inclusive and thorough explanation of the process as well as guides to help.

I can resist just fine, cancelled my preorder when it was announced and have absolutely no intention of ever dealing with Steam or Valve ever again.  I gave my word on that and when I give my word, it may as well be chiseled in stone because I don't ever go back on it.  It's called integrity.  ;]

Is there any way to change the orange ornamentation on the Advent Rebel Titan to teamcolor?

It will look a bit crappier after you did it too as you'd have to modify the cl which is in compressed DDS. The thing about compressed DDS is they are lossy images unlike compressed TGA which is lossless in detail.

I already did look into the cl and da files (for my unschooled eye it looks like the da files is for glowmaps and similar stuff, like the honeycomb pattern on Advent ships), but I couldn't find any trace of how the teamcolored areas are marked in either file.

Those places that do have teamcolors, only show a normal grey texture in the cl file.

Here's a little comparison-shot I made. On the right is a piece of the Titan_PsiRebel-cl.dds and on the left is, how the same spot looks ingame: http://imageshack.us/f/822/titanpsirebcomposite.jpg/ (If anyone wonders I got that angle on the ingame screenshot of the titan by turning the camera upside-down thanks to the "Camera: Enable Twist" option, to make the comparison with the texture file easier).

I viewed the files both in Irfanview (just for the first quick look) and Photo Impact, but both times without any success in figuring it out. Do I need another programm for this?

Ah, that explains how I could overlook them... I used an outdated version of Photo impact that didn't support alpha channels.

But with GIMP 2.0 I can see them now. Thanks for the help so far

Edit:
Well... the first attempt didn't go so well, but I'll get there eventually!

Edit2:

But the second attempt met with success, even though it was just a tiny area to work out how it's done.

Short answer: You need the planet's entity, mesh, and texture files, you'll need the entity and any other related files for their effects.  Put those in your mod.  Then you'll have to copy the sections in the galaxy scenario def file for the planets that you've added and adjust the section counts accordingly.  Add in the planet info and special effects in the string file and adjust the count accordingly as well.  Someone else can expand upon this since I'm in a hurry and can't spend an hour typing it all out.

It will take more info than that to help.  Essentially that happens a lot when a file is set up to use something it shouldn't.  putting an incompatible ability on a unit, missing meshes, etc.

Yes--starbase meshes have a lot of "stuff" in them and some of it isn't normal on a ship.  If you look at a TEXT version of the mesh file, you'll see the ability points and all--some are starbase specific.

Thanks for the answer Stant, but yeah someone expanding on that would be help as....I can only figure out about half of that.