Outlook Web Access doesn't need the incoming/outgoing/domain server info. That's the whole point of it; you access it from the web rather than the mail app.
As said above, your settings should be provided by IT. For Web Access, they may have a different address from default for the PDA view, e.g.
www.exchange.company.com/PDA.
Do you want to set up an exchange server account on your PDA instead of/as well as OWA?