So you want all that area under the cab rear window (currently red/black/silver) to be black? Pretty easy, you just need to remap them. Here's how in BinEdit:
- Press Spacebar to cycle through the faces of the model. The currently selected face is tinted purple (you might find it easier to see if you turn the textures off, so the model is drawn in just grey).
- When you get to a face that is part of that surface you want to change, press F to 'tag' it. Tagged faces are tinted green. If there is more than one face making up that surface, keep cycling and tagging until you have all the faces tagged.
- Open the Groups menu and select 'Map Face Group to Texture'. The BinMapper opens, showing a wireframe of the faces laid over one of the textures of your truck. You may need to click the Layout button for them to be arranged into something resembling the right shape.
From the drop-down box at the top you can select a texture - for what you want to do pick one with some black space on it. On the right, there is a cluster of four buttons. The first (upper left one) lets you select the vertices (red points at the corners of the faces) to manipulate in the mapping window at the right by dragging a box around them or shift-clicking each one (they turn green when selected). The other three buttons let you let you move the group around (upper right), rotate (lower left) and resize (lower right), all by clicking and dragging in the mapping window. If you select all the vertices (so they are all green) you can move them all by clicking and dragging in an empty space of the mapping window, or (if they are unselected = red) you can move them one by one by clicking on each point and dragging it.
All you need to do is size and move that wireframe so it is totally positioned over a black area of the texture, and then the corresponding part of the model will be painted black (it doesn't matter if the wireframe is all smushed up to make it fit). If you have the Preview box checked (top right of BinMapper window) you should see the texture mapping change on the model in real time as you move the wireframe around, which should help understand what you're doing.
http://binedit.com/help/
