OWA, MS Exchange Sync & 3CX

We are planning to implement the 3CX VOIP PBX system in our company, and it allow for the integration of MS Exchange in order to sync the contact databases. Below is a link to the instructions, where they request the FQDN of the Exchange OWA.

http://www.3cx.com/docs/exchange-ldap-phonebook-directory/#h.8zz4zl3zmol

We haven't had a chance to test this yet, as our services are not yet setup. Any thoughts on whether this will work, and what URL we may use for the OWA URL?