the user needs to exist first prior to adding to a group. So, use createusers first followed by addusers. The only way to get around the sync problem is to run the tabcmd via a script after your sync runs.
Yes I figured out the solution. First need to add the user to the site and than you can create a native group and add those users to that group and let them authenticate against AD so you don't need to worry about the sync issue. Also I can create file containing ad users list which I can ran on nightly so it will be updated every night or as needed.