IPad Wi Fi with Exchange 2003

i just got the new ipad and am trying to configure it with my exchange 2003... active sync is enabled in global setup and for individual users as well. when i create email account it says unable to verify account information...and when open mail tab it says connection to the server failed.
Exchange 2003 running without RPC over HTTP and SSL...webmail is used everywhere..ppl connect to exchange thru Cisco VPN from home...

any ideas what is missing on my server or anything else?