passing a date value is not updating the table

Hi All, have the follwoing stored prcoedureCreate procedure Test( @TestDate1 smallDatetime = NULL, @TestDate2 smallDatetime = NULL, @TestDate3 smallDatetime = NULL,)ASUpdate TestTable Set @Col1 = COALESCE(@TestDate1, @TestDate2, @TestDate3) I am passing Exec Test 12/23/2011, '', ''Nothing is getting updated. I am passing the date as a string from my .net code. Do I need to pass it as a datetime since there is no smallDatetime .net side.