SQL 2012 :: Datediff - Query Does Not Work With Yyyyddmm Format

I have two dates '2014-25-03 01:02:03' & '2014-26-03 01:02:03' (yyyyddmm).

I need the difference between two dates in hh:mm:ss format.

I tried following query

declare @mindate datetime='2014-03-25 01:02:03'
declare @maxdate datetime='2014-03-26 02:03:04'
select cast(
(cast(cast(@maxDate as float) - cast(@minDate as float) as int) * 24) /* hours over 24 */
+ datepart(hh, @maxDate - @minDate) /* hours */
as varchar(10))
+ ':' + right('0' + cast(datepart(mi, @maxDate - @minDate) as varchar(2)), 2) /* minutes */
+ ':' + right('0' + cast(datepart(ss, @maxDate - @minDate) as varchar(2)), 2) /* seconds */

This works fine but as you can see the date I have used in the query is in yyyymmdd format.

The query does not work with yyyyddmm format

The expected answer is =25:01:01.