UV mapping: Texture Paint paints wrong faces and other stuff

Hey com.

I have a question regarding to the UV mapping in Blender. I modelled a little cartoonish dinosaur and I want to texture it now. I use a mirror modifier.

Here is what I do:
Select the object, go into edit mode, select all the faces I want to unwrap, click U -> unwrap.

Problem: Sometimes I got a unwrap of the whole dinosaur and not just the selected faces.

This happened in 2.49 as well as in the 2.5 beta. Is this a bug or did I do something wrong? I tried to reproduce it, but now it works.

(I have ~20 different version of this modell, the second picture is a later version where I screwed up. I started the texturing all over again later)

Question 1:
Especially when I got the whole object unwraped I have the following question: How can I delete parts of the unwraped mesh in my UV/Image editor? For example, if I selected to many faces and then just want to delete them in the UV editor without unwrap again.

Question 2:
How can I delete “unwraps” (the things you can select in the uv editor in the dropdown box. I guess they are just called “datablock”?!)
In Blender 2.5 beta the only thing that worked was to shift+click on the X, save the blender file, restart blender and open the file again.
Is there another solution?

When I unwraped my object/faces and I want to paint it, I click on “image” -> “new image” -> “ok”. Now I have a datablock called untitled or whatever and the uv editor is filled in my selected color. In draw type texture I can already see it, but not in the final render.
I can now paint it via texture paint in my 3d window, or with “enable image painting” in the UV editor. When I’m done I save the uv map image (test.tga) go to materials -> texture, select an image texture and load the test.tga.
Is that the way it’s supposed to be or is there another solution to it?

The color is not on the right place. For example, I painted the belly white but when I render the belly is still green (object color) and some other parts are white (some of the head, the hand, the tail,…). Even when I paint via texture paint. And with draw type textured enabled, I can see that only the belly is painted.
What did I do wrong?

What is TexFaces for? Do I just lose the information of the color and use the color of the uv map instead? (in my case the color I selected as background for my uv map)

I’m not a absoulte beginner, but I never used uv mapping. I did some tutorials on that subject, but they didn’t help me and I’m kinda stuck now. A simple test with a cube that I unwraped and painted 1 to 6 on it worked fine. (although in blender 2.5 beta I got 64 untitled datablocks untitled.001 to untitled.064 after I unwraped the cube o.O)

Thanks for your help.
regards DiLer