You can get the souce codes either by:
The easiest way is to download the zip file, unpacking it and starting editing any of the sample themes in the skins folder. Example:
As you can see, there are button movieClips and button bitmap images. If you just want to change the look of button icons, the easies way is to replace the bitmap images. First, make your icons ready. Download this archive as an example: black_diamond.zip
Now you need to replace the images. For each bitmap item in the library, you need to double click it to open properties then click Import and navigate to according bitmap file. E.g. for button left:
You need to repeat this for every bitmap image in the Buttons folder. Similarly replace the icons in the Zoombar assets folder.
After you are done, hit Test movie (Ctrl+Enter) to see your new icons in the player.
Moving the icons in the .fla file has no effect.
The 3DRT Flexi fits any widht/ height defined in the html page. This is done by actionscript code, which defines that e.g. the left arrow button is always in bottom left corner and fullscreen button in bottom right corner.
This RotateToolTheme.as actionscript file is located in com\yofla\rotateTool\view\components folder in the skin archive. You can edit it using e.g. FlashDevelop for Windows or any of your favourite text editor.
In this file, locate the function resize:
As you can see, the button positions are defined in code. To change the position of the buttons, you need to rewrite the commands which define their positions. E.g. for the vertical buttons theme the RotateToolTheme.as file looks like this: RotateToolTheme.as
Editing the .as file might be difficult, but it gives you the possibility to achieve any button placement you like. If you have any questions feel free to contact me at firstname.lastname@example.org.