how to add roster with subscription mode "both"

i'm using smack 3.1.0, and when i add a roster,i can't get subscription "both". who can help me? below is my code:

Roster.setDefaultSubscriptionMode(Roster.SubscriptionMode.accept_all);
Roster roster = connection.getRoster();
roster.createEntry("buddy@test.com","me",null)

after the code execution, i observed in openfire the subscription is "to"