Here is my example, hope this help you a bit.
My table is:
Id(int) SortFields(varchar(50))
1 28-08-2004
2 29-08-2004
3 01-01-2001
4 15-11-2000
SQL query:
SELECT *
FROM
(SELECT [Simply].Id, CONVERT(datetime, [Simply].SortFields, 105) AS FDate
FROM [dbo].[Simply]) AS tb
ORDER BY tb.FDate ASC
And result:
Id FDate
4 2000-11-15 00:00:00.000
3 2001-01-01 00:00:00.000
1 2004-08-28 00:00:00.000
2 2004-08-29 00:00:00.000