QDataWidgetMapper and QComboBox

Hi, I try to connect my QSqlRelationalTableModel with QDataWidgetMapper like it's in this article
http://doc.trolltech.com/qq/qq21-dat...toofferchoices

I set relation between my user table where there is a field id_user_type and description table where are id_user_type and name.

Then I mapped this data from model to QComboBox everything work fine till names differ from each other.

When names are the same the combobox set position at first item with this name, so it's going by name not by id_user_type.

Is it a bug or i do something wrong?