NTP Key verification

I'm trying to configure my BIG-IPs to use NAT symmetric key authentication but I'm having a hard time verifying that it's working. I followed SOL14120 to configure the key and force NTP synchronization only if authentication is successful. When I take a traffic capture I can see NTP is functional but there aren't any entries for "Key ID' or "Message Authentication Code" as Wireshark indicated I should see on a NTP with MD5 capture. https://wiki.wireshark.org/NTP

Any help would be appreciated.