create procedure sp_WithDefaultParam
   @Param1 int=null,
   @Param2 int=null,
   @Param3 int=null
as
begin
   declare
     @RetVal int

   set @RetVal= 0 

   select @Param1, @Param2, @Param3

   return(@RetVal)
end

cmd.CommandType=CommandType.Text;
cmd.CommandText="{call sp_WithDefaultParam}";
rdr=cmd.ExecuteReader(); // NULL
rdr.Close();

cmd.CommandType=CommandType.Text;
cmd.CommandText="call sp_WithDefaultParam(?)";
cmd.Parameters.Add("Param1",OleDbType.Integer).Value= 1 ;
rdr=cmd.ExecuteReader(); // Тут падаем с error:	"[Native Error code: 2812]\n[DataDirect ADO Sybase Provider] Stored procedure 'call sp_WithDefaultParam(@1)' not found. Specify owner.objectname or use sp_help to check whether the object exists (sp_help may produce lots of output)." Хотя... Мо это и особенность Sybase ASE only...
rdr.Close();

cmd.CommandType=CommandType.StoredProcedure;
cmd.CommandText="sp_WithDefaultParam";
OleDbCommandBuilder.DeriveParameters(cmd);
rdr=cmd.ExecuteReader(); // NULL
rdr.Close();

@person_BirthDay as varchar ( 20 )

create procedure person_search
   @person_BirthDay date=null,
   @person_SurName varchar( 20 )=null,
   @person_FirName varchar( 20 )=null,
   @person_SecName varchar( 20 )=null
as
begin
   select
     Person_SurName,
     Person_FirName,
     Person_SecName,
     Person_BirthDay
   from
     v_Person
   where
     ((@person_SurName is null) or (Person_SurName like @person_SurName))
     and ((@person_FirName is null) or (Person_FirName like @person_FirName))
     and ((@person_SecName is null) or (Person_SecName like @person_SecName))
     and ((@person_BirthDay is null) or (Person_BirhtDay=@person_BirthDay))
end

....
cmd.CommandType=CommandType.StoredProcedure;
cmd.CommandText="person_search";
SqlCommandBuilder.DeriveParameters(cmd);
cmd.Parameters["@person_SurName"].Value = (tmpString=TextBoxSurName.Text.Trim())!=string.Empty ? object(tmpString+"%") : DBNull.Value;
cmd.Parameters["@person_FirName"].Value = (tmpString=TextBoxFirName.Text.Trim())!=string.Empty ? object(tmpString+"%") : DBNull.Value;
cmd.Parameters["@person_SecName"].Value = (tmpString=TextBoxSecName.Text.Trim())!=string.Empty ? object(tmpString+"%") : DBNull.Value;
cmd.Parameters["@person_BirthDate"].Value = (tmpString=TextBoxSurName.Text.Trim())!=string.Empty ? object(DateTime.Parse(tmpString)) : DBNull.Value; // здесь - схалявил. Нуна, ессесно, более железобетонно...
rdr=cmd.ExecuteReader();
....

asp:SqlDataSource

 asp:SqlDataSource