SSRS Report Parameter

All,
I have a report that needs to return a number of columns from a table based on 2 parameters [StartDate & EndDate [datetime]].

Here is my dataset
Select * from table1 where start_date between @StartDate and @Enddate.
In table1 [start_date datetime ,example value=[3/6/2008 6:41:47 PM]]

My problem is how do I convert the start_date to [3/6/2008] within my Dataset.
Something like the below.[I get an error when I do the below]
Select * from table1 where convert(varchar(10),start_date,111) between @StartDate and @Enddate.

The reason for doing this is because when I pick, StartDate as 01/01/2008 and EndDate as 1/31/2008.My report only return's values of 01/01/2008 to 01/30/2008.The items that falls on 1/31/2008 do not get displayed as the datasets does not consider time when comparing,but only the date part.

Do give me a suggestion,solution to this.Thank You in advance!