Convert date to integer in parameter

Now I have a stored procedure that accepts the date as integer(140213), but inside SSRSI need to convert the date selected in date parameterto to the integerone mentioned earlier.

Now I'm trying to achieve this with 2 parameters (date and convert), one of which allows you to select a date, and the second - an attempt to convert the date to int. Within the second parameter in the default value, I have:

=FormatNumber(Format(Parameters!date.Value, "yyMMdd"),0)

The second parameter is set to internal, and the data type to integer.

When I try to run this report, I get an error

The property 'DefaultValue' of report paramater 'convert' doesn't have the expected type.

Any idea on how this can be achieved?