I want a metrics report on total work item creation by type  on a given day in an iteration. I am using the Request Creation Metric -> Creation Date. I can filter on date by explicitly selecting dates and this gives me a filter that looks like

[Date] in ([Request Creation Metrics].[Creation Date].[Date].[Year]->[all].[2014])

What I want is to be able to pass in the dates for the iteration using ?startDate? and ?endDate? but using the the format that I would typically use for ODS gives me an error

Note that using nesting with iteration and date won't work for me as I am trying to track items that have been created both before and after (sic) the iterations date so I want to select the iteration's dates and then add some tolerance