SQL & PL/SQL

Dear All,

It would be great if someone could help me. I am trying to use UTL_SMTP to email with a csv file as attachment. I do get an email with a message but no attachment arrives with it.
In fact the code used for attaching the csv file gets appended in the message body in the email.

CREATE OR REPLACE PROCEDURE test_mail
AS
SENDER constant VARCHAR2(80) := 's.mitra@xxxx.ac.uk';
MAILHOST constant VARCHAR2(80) := 'mailhost.xxxx.ac.uk';
mail_conn utl_smtp.connection;
lv_rcpt VARCHAR2(80);
lv_mesg VARCHAR2(9900);
lv_subject VARCHAR2(80) := 'First Test Mail';
lv_brk VARCHAR2(2) := CHR(13)||CHR(10);
BEGIN
mail_conn := utl_smtp.open_connection(mailhost, 25) ;
utl_smtp.helo(mail_conn, MAILHOST) ;
dbms_output.put_line('Sending Email to : ' ||lv_brk||'Suhas Mitra' ) ;
lv_mesg := 'Date: '||TO_CHAR(sysdate,'dd Mon yy hh24:mi:ss')||lv_brk||
'From: <'||SENDER||'>'||lv_brk||
'Subject: '||lv_subject||lv_brk||
'To: '||'s.mitra@xxxx.ac.uk'||lv_brk||
'MIME-Version: 1.0'||lv_brk||
'Content-type:text/html;charset=iso-8859-1'||lv_brk||
' boundary="-----SECBOUND"'||
''||lv_brk||
'-------SECBOUND'||
'Some Message'
|| lv_brk ||
'-------SECBOUND'||
'Content-Type: text/plain;'|| lv_brk ||
' name="xxxx.csv"'|| lv_brk ||
'Content-Transfer_Encoding: 8bit'|| lv_brk ||
'Content-Disposition: attachment;'|| lv_brk ||
' filename="xxxx.csv"'|| lv_brk ||
lv_brk ||
'CSV,file,attachement'|| lv_brk || -- Content of attachment
lv_brk||
'-------SECBOUND' ;
dbms_output.put_line('lv_mesg : ' || lv_mesg) ;
utl_smtp.mail(mail_conn, SENDER) ;
lv_rcpt := 's.mitra@xxxx.uk';
utl_smtp.rcpt(mail_conn, lv_rcpt) ;
utl_smtp.data(mail_conn, lv_mesg) ;
utl_smtp.quit(mail_conn);
EXCEPTION
WHEN utl_smtp.transient_error OR utl_smtp.permanent_error THEN
NULL ;
WHEN OTHERS THEN
dbms_output.put_line('Error Code : ' || SQLCODE) ;
dbms_output.put_line('Error Message : ' || SQLERRM) ;
utl_smtp.quit(mail_conn) ;
END;