You don't, at least I didn't on the CAS array I built last week. I believe it'll use the CAS servers in that AD site as a CAS array exists within the site only. If you do a Get-ClientAccessArray, you should see the Members attribute set to your CAS servers already.
Don't forget that any mailbox databases created before the CAS array will need to be associated, i.e. do a Get-MailboxDatabase and examine the properties of the RpcClientAccessServer attribute. From: farooq.ahmed [mailto:farooq.ah...@aku.edu] Sent: 15 March 2010 12:22 To: MS-Exchange Admin Issues Subject: Exchange 2010 ClientAcess Array. Hello folks, I have installed two CAS servers and Windows 2008 r2 NLB is also configured. I did run Exchange commands to create Exchange 2010 ClientAcessArray . How do I associate these two servers with ClientAccess Array. Thx. P Save a tree. Don't print this e-mail unless it's necessary _____ This e-mail may contain information that is privileged or confidential. If you are not the intended recipient, please delete the e-mail and any attachments and notify us immediately.