Daoudi Youcef , I haven't worked with WIEN2K explicitly, but familiar with other DFT codes. Let me see if that experience would be of any use to you!
Can you enlighten me with some information on the structure of output files of bands calculation? What are the information available to plot? Do you have your k-point and energy for each bands written neatly as a file already or do you need processing your WIEN2K output into a plottable xyz format? In what format the orbital projection onto bands is available?