Sorting report columns for PL/SQL report

Question

I have created a report of type "Pl/Sql function body returning Sql query" in which I am generating the column names within the query. I would now like to make the first three of these columns sortable. But when I click on the "sort" box for the first three columns, all my column names suddenly switch to "Col 1", "Col 2" etc.
As you can see by the following snippet from the PL/SQL that generates the query, the column names are data driven, so I'm not in a position to declaratively rename each column. As it happens, the first three columns names are fixed, but all the subsequent column names are data driven.
Suggestions on how to make the first three columns sortable while preserving the generated column names of the remaining columns?
thanks
susan weber
declare
query varchar2(4000); -- query
begin
query := 'select first_name "First Name", last_name "Last Name", encounter_date "Encounter Date" ';
for c1 in (select distinct attr_src, attr_code, attr_text, sequence_number from finding_vt)
loop
query := query || ', (select val_text from finding_vt vt where vt.encounter_id = e.encounter_id and vt.attr_src = ''' || c1.attr_src || ''' and vt.attr_code = ''' || c1.attr_code || ''' and sequence_number = ' || c1.sequence_number || ') "' || substr(c1.attr_text,0,30) || '"';
END LOOP;
query := query || ' from patient pat, encounter e where pat.patient_id = e.patient_id';
return query;
end;

Answer 1

This turns out to be related to the choice of "use generic column names" v. "use query specific column names".
I had chosen "use generic column names" just to get past the initial creation page. I then debugged the query creation sql, but never changed that setting back to "use query specific column names". The fix is to choose "use query specific column names".