Sounds ok this way :
PT(GraphicsStateGuardianBase) gsg = ABuffer->get_gsg();
GLTextureContext *GLtex = DCAST(GLTextureContext,ABuffertexture->prepare_now(gsg->get_prepared_objects(),gsg));
GLuint texA = GLtex->_index;
I’m now moving OpenGL & DirectX textures back and forth!
Thanks again for your help