Dim MySort As New SortExpression
MySort.Add(New SortClause(New EntityProperty("YourNewColumn"), Nothing, SortOperator.Ascending))
Don't use the e.Sorter
Rather pass the above mentioned SortExpression to the FetchTypesList method.
adapter.FetchTypedList(e.ContainedTypedList, e.Filter.PredicateExpression, e.MaxNumberOfItemsToReturn, MySort, e.AllowDuplicates, e.PageNumber, e.PageSize);