In the SSRS tutorials on MSDN it says you can format a text box much like you would in vb.net. If I have a date field being returned as say 20081225,(don't ask why) I want to format the text box so that it displays 2008/25/25. I tried this:

=Parameters!deliver_dt.Value.ToString("yyyyMMdd")

but it tells me I am passing in the wrong number of arguments. What am I doing wron and how to fix it.