Today I installed a Exchange 2010 CAS cluster using (Windows) NLB. After some final preparation I followed Microsoft best practices for creating a CAS cluster. (Microsoft recommends creating a CAS cluster also when you’re only using one CAS cluster).
This is how you can do that :
New-ClientAccessArray -Name <NameOfArray> -Fqdn <NLB Name>
Exchange asked for your site name, you can find this name in Active Directory sites and services.