FTP through a proxy

Hi,

I am trying to access a site through ftp. I've run the following
commands;

export ftp_proxy=http://<IP address of the proxy server>:8080
export http_proxy=http://<IP address of the proxy server>:8080

But still when I try to access the ftp site through the command ftp
<servername> it waits indefinitely.

Even commands like 'curl www.google.com' or 'wget www.google.com' are
also not going through.

I am using RHEL 4 linux machine. The proxy server is a windows box. Is
there any other setting I need to check?

Thanks,
Sankar