datetime parameter in coldfusion report builder

Hi,

I'm trying to create a report in coldfusion report builder that takes 2 parameters; startdate and enddate. These two parameters correspond to two fields in my sql database. However, both the fields are of type datetime and I can't work out how to insert them into my report? If I change the type in the report to string I get an error message so it's not that. Had a look on the internet but haven't been able to find any answers.

I'm using coldfusion mx7

Does anybody have an idea?

Thanks

Stevie