[Set order number for group in IReport]

Hi

I have a group in my report. Now, i want create order number for this group.

No    Group's name    Record
1       grp1-------------------------------
                                record1
                                record2
2       grp2------------------------------
                                record3
                                record4

 

I was created variables "STT" , but don't run. Detail:

 - Variable Class; java.lang.Integer

 - Calculation: Nothing

 - Reset type: None

 - Increment type: Group

 - Variable Expression:    ($V{STT} == null?0:$V{STT}) + 1

 - Initial Value Expression: new Interger(0)

And i set Evaluation Time: Group

Please help me!