Unable to sync NTP v4 client to Windows AD server

I realize that Microsoft doesn't even recommend using a windows server as a time service, however I don't have a choice -- closed network in a windows centric shop. It became an issue when the newer Solaris 11 systems could not sync to the AD servers which come with NTP v4 ( 4.2.8p10 ). It does work for the Solaris 10 servers using the older v3 (xntpd) as a client. I tried disabling the older client, and enabling the ntp4 client ( 4.2.8p9) on the Solaris 10 systems. So even though it had been working, and uses the same ntp.conf, the v4 client fails to sync. Anyone have any suggestions on a possible tweak to sync a NTP v4 client to a Windows 2012 R2 AD server? **ntp.conf** server AD_SVR1_IP prefer iburst server AD_SVR2_IP peer rac-node2 My long term plan is to get the network team to enable a NTP service on one of their device that we all point to. Thanks