SQL Server 2005 Query With Date Function

I wrote a function and a SQL to get the  3 columns Date,Total Orders
& Amount, for dates between Date Started and Date Completed if I
pass different Dates in the SQL I get the correct result but if I pass
same dates then I don't get the result I am looking for .

For Instance,if I give Date From=1/02/2008 ;Date To=1/8/2008(Different dates )I am getting values for all the three columns.
But I give same dates for  Date From=01/02/2008 ;Date To=01/02/2008 then I am not getting the records.

Some how I could not trace what could be the error in my SQL /Function.

I appreciate if I could get some work around for this.

Thanks!
 
 
Function:create function dbo.CreateDateList(@start datetime, @end datetime)
returns @t table ( [date] datetime )
as
begin
if @start is null or @end is null
return

if @start > @end
return

set @start = convert(datetime, convert(varchar(10), @start, 120), 120)
set @end = convert(datetime, convert(varchar(10), @end, 120), 120)

while @start < @end
begin
insert into @t ( [date] ) values (@start)
set @start = dateadd(day, 1, @start)
end

return
end

---------SELECT qUERY----------

SELECT Convert(Varchar(15), l.[date],101)as Date,COUNT(o.OrderID ) AS TotalOrders,ISNULL(Round(SUM(o.SubTotal),2),0) AS Amount , 1 as OrderByCol
FROM dbo.CreateDateList(@DateFrom , @DateTo) l
LEFT OUTER JOIN orders o ON o.Datecompleted >=Convert(Datetime, l.[date],101) and o.Datecompleted < dateadd(day,1,convert(Datetime, l.[date],101))
WHERE StoreID=@StoreID GROUP BY Convert(Varchar(15), l.[date],101)
Union
SELECT 'Grand Total' as Total,NULL AS TotalOrders, ISNULL(Round(SUM(o.SubTotal),2),0) AS Amount, 2 as OrderByCol
FROM dbo.CreateDateList(@DateFrom , @DateTo) l
LEFT OUTER JOIN orders o ON o.Datecompleted >=Convert(Datetime, l.[date],101) and o.Datecompleted < dateadd(day,1,convert(Datetime, l.[date],101))
WHERE StoreID=@StoreID
Order by Date