Geoshader, many instances, and bsp2

[atap3d]

Hi.
I'm trying to write geoshader.
I have a very simple code.

#include <fstream>

#include <shader.h>
#include <geoshader.h>

void add_vector(miScalar x, miScalar y, miScalar z)
{
    miVector v;
    v.x = x; v.y = y; v.z = z;
    mi_api_vector_xyz_add(&v);
}

miTag miaux_object(const char* name)
{
	int i; 
    miVector v;

	miObject *obj = mi_api_object_begin(mi_mem_strdup(name));

    mi_api_object_group_begin(0.0); 

    add_vector(-.5,-.5,0);
    add_vector(.5,-.5,0);
    add_vector(.5,.5,0);
    add_vector(-.5,.5,0);
 
    add_vector(0,0,1);
 
    for (i = 0; i < 4; i++) {
        mi_api_vertex_add(i);
        mi_api_vertex_normal_add(4);
    } 

    mi_api_poly_begin_tag(1, 0);
    for (i = 0; i < 4; i++)
        mi_api_poly_index_add(i);
    mi_api_poly_end();

    mi_api_object_group_end();
 
    return mi_api_object_end(); 
}

extern "C" DLLEXPORT int mrgeoshadertest_version(void) {return(1);}

extern "C" DLLEXPORT miBoolean mrgeoshadertest(
    miTag           *result,
    miState         *state,
    miTag           *paras)
{
	char iname[100];
	miTag objtag = miaux_object("hi");
	miInstance *inst;

	for (int i=0; i < 10; i++)
	{
		miMatrix matrix;

		sprintf(iname, "hi%i", i);
		inst = mi_api_instance_begin(mi_mem_strdup(iname));

		mi_matrix_ident(matrix);
		matrix[14] = (float)i;

		mi_matrix_copy(inst->tf.local_to_global, matrix); 
		mi_matrix_invert(inst->tf.global_to_local, inst->tf.local_to_global);

		mi_geoshader_add_result(result, mi_api_instance_end(0, objtag, 0));
	}
	return miTRUE;
}

I'm using maya 2009(mental ray 3.7.1.26, Jul 30 2008, revision 26576)
It is rendering successful. I see set of squares. But, if I change "scanline" option to off and "acceleration method" to bsp2, it is dont rendering. the object is missing. I dont see set of squares. Why? I want use bsp2 and scanline-off. How can i fix my code?