Setting the return query fields

[Dhanushka Samarakoon]

Hi,
I would like to solr to return to record from /exampledocs/hd.xml when I
search for the value "6H500F0" (which is the ID field for the 2'nd record in
that file).
I know there is a setting that I should change to get this done, but I can't
locate it.
Field name ID is alread included in schema.xml file.
Thanks,
Dhanushka