Nhibernate mapping one to zero or one - with left join

Nhibernate mapping one to zero or one - with left join

I have class Place which may or may not have one User.
//I have nothing on User related to Place
public PlaceMap()
{
Id( x=> x.Id, "id").GeneratedBy.Identity();
References(x =>
x.UserManager,"user_manager_id").Nullable().Cascade.All();
}
When querying over Place, I want always to left join since it is Nullable.
The problem is that the generated sql has inner join.
the query:
var queryList = _dalSession.CreateCriteria<T>();
maxQuery.CreateAlias("UserManager", "UserManager");