Copy fields when form is saved

Very simple one,

When I add a new sales quote I want the Total Value edit box to be copied to my Expected Value edit box, as the data is not added to the table yet I thought it would all be available as stings in the edit boxes, hence the following:

If pVal.EventType = SAPbouiCOM.BoEventTypes.et_FORM_DATA_ADD And pVal.FormType = 149 And pVal.Before_Action = True Then

oApp.Forms.Item("149").Items.Item("oEdit4").String = oApp.Forms.Item("149").Items.Item("29").String

End If

Please excuse any stupidity, its a steep learning curve......

Thanks,

Dave.