Filter for Date Range on Timesheet Report

Hi folks,

Does anyone know how to use text mode and put a filter on the Date Range field? The Date Range field is a text mode field available in WF's off the shelf report 'All Open Timesheets'. I'd like to create a copy of this report and put a filter on it to only show data based on a Date Range of $$TODAY-4w (the last 4 weeks of timesheets). Since this field is only available in text mode, from what I can see, does anyone know how to do a text mode filer for the above date range (4 weeks)?

Here's the text mode for the Date Range field:

link.linkproperty.0.name=ID

link.linkproperty.0.valuefield=ID

link.linkproperty.0.valueformat=val

link.page=/timesheetOpenTime.cmd

link.valuefield=objCode

listsort=atDateAsAtDate(startDate)

namekey=daterange

querysort=startDate

sortOrder=1

sortType=desc

textmode=true

valueexpression=CONCAT(DATENOTIME({startDate}),' - ',DATENOTIME({endDate}))

valueformat=val

width=80

Thanks.

Nick