Creating flatfile from edi 856 x12

Hello ryan,
Thanks for your quick response.
i have 856 edi document is coming as input and i have used
envelope process , and convertTOvalues services to create to idata object.
then what is the next step i have to use to convert this idata to flatfile.
i have to create positional flatfile.
any help is appreicated.
Thanks in advance,
rao