how to transfer . bam to Maya 201* without losing Textures?

Hey,
I use Panda 3D SDK 1.9.4 Python 2.7
I convert .bam to a Maya 2016 or later compatible extension(.bam 2 .egg 2 .obj)
I lose textures when converting and it also is gone when converting back to a .bam

anyone know how to fix it