Crystal 7 stored procedure pass formula as parameter

Is it possible to pass a formula as the paramter of a stored procedure? I need to do this so the user is prompted for a date parameter instead of a datetime parameter. After the user enters the date in the parameter I want to then create a formula to change the date to a datetime field then pass that value to the stored procedure. In other words, I have a crystal 7 report running against a sql server 2000 database stored procedure that has a parameter of datetime. I don't want the user to be prompted for a datetime, just a date. This was easy to do in crystal 9 using a command but I cant figure out how to do it in crystal 7.  Thanks in advance,