How to enable SNI on Big-IP Version 11.5.3 (Build 1.16.167)

I have a VIP where I'm trying to apply two client ssl profiles, intending to use SNI. The problem is, when I apply the second profile, it says:

0107149c:3: Virtual server /ESAI/lb-drupal-tuftsmagazine.tufts.edu-443 has more than one clientssl/serverssl profile but none of them is default for SNI.

By searching these forums, (in particular this page it seems I need to add Server Name to the client ssl profile, but that field isn't present on my system. On the ssl client profile page, there is no "Server Name" field, no mention of SNI anywhere on the page.

Is this a licensed feature, or something I don't have? Has the control been relocated in my version of Big-IP? Or something?

Thanks...