SQL & PL/SQL :: Retrieve HTML Using Oracle And Setting Correct User Agent

i need to retrieve html using oracle and setting the correct user agent.I used the ut_http package and his fuction utl_http.request_pages.

I worked perfectly for me, execpt that i could be able to setup the correct user-agent.I read the documentation and i found that this instruction utl_http.set_header(req, 'User-Agent', 'Mozilla/4.0'); should fix my problem, but when i used it, nothing changed and the webserver didn't recognize the correct user agent.

I post downhere a piece of the pl-sql procedure i made (it seems that i could find the correct "link" between utl_http.set_header instruction and utl_http.request_pieces instruction)

while(ng < nmax)
loop
ch_in:=p_mese_elab||'-'||ng;
url:=url to retrieve;
req := UTL_HTTP.BEGIN_REQUEST(url);
UTL_HTTP.SET_HEADER(req, 'User-Agent', 'Mozilla/4.0');
resp := UTL_HTTP.GET_RESPONSE(req);
RISULTATO:=utl_http.request_pieces(url,99999);
delete temp_esamina
where data_ril = trunc(to_date(ch_in,'yyyy-mm-dd'));
[code]...