How to rip BGs from Batman The Brave & The Bold DS

[MatreroG]

Hi, I´m would like to rip BGs from Batman The Bave & The Bold from DS.
What kind of tools would have to use? I tried with the Desmume emulator and with Tinke, the result is a completely black image or, in the best of cases, an image with all the layers together.
What others options I have?

Thanks in advanced.