tsearch2 headline() query subselect help

guys,
how'd i make this query work?
select headline(select column_1 from table_1 where
to_tsvector(column_1) @@ to_tsquery('ftp'),'ftp'::tsquery);
ERROR: syntax error at or near "select" at character 17

when i break it, it works fine, like so
# select headline('ftp sftp','ftp'::tsquery);
headline
----------
<b>ftp</b> sftp
(1 row)
# select column_1 from table_1 where to_tsvector(column_1) @@
to_tsquery('ftp');
column_1
----------
ftp sftp
(1 row)
where
# select column_1 from table_1 where column_index=1;
column_1
----------
ftp sftp
(1 row)

and how'd i add rank() to this query?
jzs
http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/