Exchange Server 2010 OWA configuration

hello all,

i am running 2 exchange servers

1. exchange 2003 (primary server ) with RPC-HTTP back end server.

2. exchange 2010 introudcued recently with test mailbox.

Internal OWA for exch2010 works fine.

My question is how to the get the External OWA working for new exchange 2010 while mailboxes are on exchange 2003( for couple of weeks).

here is full story.

this is how my normal mail flows.

forefront –> checkpoint firewall –> DMZ (smtp gateway) –> checkpoint firewall—> exchange 2003 .

OWA for exchange 2003

owa external address :- webmail.domain.co.uk

external browser –> DMZ DNS redirect —-> internal exchange address.

My question is that how make it to work in same way on exch 2010 as it is working now .

Regards,