What kind of values are coming from your DataSource? Here is code that works for double values coming from the datasource in the attached sample.
Dim style As GridStyleInfo = Me.gridDataBoundGrid1.Binder.InternalColumns("$amount").StyleInfo
style.CellType = "Currency"
style.CurrencyEdit.ClipMode = Syncfusion.Windows.Forms.Tools.CurrencyClipModes.ExcludeFormatting
forum11780_1942.zip