How to extract BLOB through OA page.

Dear Gurus,

I am trying to extract pdf file which is stored in table as BLOB column.

So what I am trying to achieve here is, When user click Payslip button their salary slip must appear through self service page.

Salary slip is already stored as a Blob column in at custom table.

I have written a procedure which is compiling fine but when Payslip button is pressed it does not bring the pdf (payslip) file as output.

Please see my procedure below.

CREATE OR REPLACE PROCEDURE XXEXTRACT_PAYSLIP  IS
      v_blob         BLOB;   
      blob_length    INTEGER;
     chunk_size     BINARY_INTEGER := 32767;