How to add referer header in external redirect?

[Whut Jia]

Hi all,
I need some help with a redirecting/referrer issue. If I do a 303 redirect in 
my module (by this way below:
apr_table_setn(r->headers_out,"Location","http://idp/login.html";);
return HTTP_SEE_OTHER;)
In order to I can see the  referrer header when jumping to the new page,how do 
I solve this??
 
Thanks,
ajxs.