system Matrix set Itemcode and itemName from diferent Items

Hi experts,

How can i do for make the following?:

I´m trying to set line in system Matrix (via oMatrix object) an itemCode and ItemName .... it seems easy, but a question is that itemname is diferent that description of itemcode which is added...in other words:

 NewItemCode = (EditText)this.mtxDocumentLines.Columns.Item("1").Cells.Item(numNewRow).Specific;
 NewItemName = (EditText)this.mtxDocumentLines.Columns.Item("3").Cells.Item(numNewRow).Specific;
 NewPrice = (EditText)this.mtxDocumentLines.Columns.Item("14").Cells.Item(numNewRow).Specific;
 NewItemCode.Value = "itemCode OF Some Item In OITM";
 NewItemName.Value = "itemName Of Another item in OITM";
 NewPrice.Value = DifLinea.ToString();
     

My problem is newItemName assignment making loose a previous assignment of ItemCode....

I´m trying with sendkeys(ctrl + tab) or something similar .... but without success...

Somebody know how its the right way??

thanks in advanced