APEX

I have a an interface whereby the user can select 1 to 60 (upper limit) columns out of 90 possible columns (using a shuttle) from one table before running a report.
To construct the SQL that will eventually execute, I'm using a "PLSQL function body returning SQL query" with dynamic SQL. The only problem is that I have to use "Generic Column Names" option to be able to compile the code and end up with c001 to c060 as the column names.
How can I use the names of the selected columns as the report headings rather than c001, C002... etc?
I do not know beforehand which columns, or how many columns or the order of the selected columns.
I know Denes K has a demo called Pick Columns but I can't access his code. I have a hunch though that he may be just using conditions to hide/show the apropriate columns.
thanks in advance
PaulP