[Zope] accessing zope site from inside the proxy server

Hi , I have my zope site running on the net. I have small problem.When iam accessing the site from inside the proxy server,old pages or cached pages are coming. I want to set a header in such a way nothing is cached in my proxy server. I had entered the following line in standard_html_header,but still sometimes pages come from cache. <dtml-call "RESPONSE.setHeader('Cache-Control','private,proxy-revalidate,no-cache,no-store')"> Does any one has the solution?Your response is of very value to me and very much appreciated. Thank you for your valuable time, regards, Dhanunjaya