ссProductList — это UltraCombo.

.......................
ccProductList.DataSource = GetProductList()
ccProductList.DisplayMember = "FullName"
ccProductList.ValueMember = "ProductID"
.......................

Private Sub ug_InitializeLayout(ByVal sender As Object, ByVal e As Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs) Handles ug.InitializeLayout
If e.Layout.Bands(0).Columns.Exists("ProductID") Then
With e.Layout.Bands(0).Columns("ProductID")
.ValueList = Me.ccProductList
.Style = Infragistics.Win.UltraWinGrid.ColumnStyle.DropDownValidate
End With
End If
End Sub