Create XML on SAP

Hi friends! I need some help!

I'm creating an XML file with the code:

g_ixml = cl_ixml=>create( ).

g_document = g_ixml->create_document( ).

lote = g_document->create_simple_element(
                   name = 'NF'
                   parent = g_document ).

nfnum = g_document->create_simple_element(
                               name  = 'nfnum'
                               value = '999999999'
                               parent = lote ).

*   Creating a stream factory and streams
g_streamfactory = g_ixml->create_stream_factory( ).

g_encoding = g_ixml->create_encoding(
                      character_set = c_encoding
                      byte_order = if_ixml_encoding=>co_little_endian ).

* Rendering into a table-based stream
g_ostream = g_streamfactory->create_ostream_itable( xml_table ).

g_ostream->set_encoding( encoding = g_encoding ).

g_renderer = g_ixml->create_renderer( ostream  = g_ostream
                                      document = g_document ).
g_rc = g_renderer->render( ).

* use only the first xml_size bytes of the xml table!!
xml_size = g_ostream->get_num_written_raw( ).

data: v_file type string.

concatenate 'C:\' 'FUL01' '.txt' into v_file.

call method cl_gui_frontend_services=>gui_download
  EXPORTING
    bin_filesize = xml_size
    filename     = v_file
    filetype     = 'BIN'
  CHANGING
    data_tab     = xml_table.

It's worked, but all tags is writed in same line:

<?xml version="1.0" encoding="utf-8"?><NF><nfnum>999999999</nfnum></NF>

So, I want something like:

<?xml version="1.0" encoding="utf-8"?>
             <NF>
                    <nfnum>999999999</nfnum>
             </NF>

How can I do this?

Thanks for any help!