GetMyeBaySelling ActiveList not filtering by DurationInDays

I am creating a call to GetMyeBaySelling using webservices/995/ebaySvc.wsdl
my c# code:
...
eBayAPIInterfaceService service = new eBayAPIInterfaceService();
GetMyeBaySellingRequestType req = new GetMyeBaySellingRequestType();
// Active List
req.ActiveList = new ItemListCustomizationType();
req.ActiveList.Include = true;
// setting this causes some kind of error and does not return anything
req.ActiveList.DurationInDays = Convert.ToInt16(45);
req.ActiveList.DurationInDaysSpecified = true;
GetMyeBaySellingResponseType resp = service.GetMyeBaySelling(req);

This returns zero listings even though I have 16 listings created within last 7 days.
NOTE THIS WORKS When I comment out the DurationInDays and DurationInDaysSpecified and i receive ALL the current listings.
I am creating a process where i do not want ALL the thousands of active listings, i just want the ones newly created within the past X days...
Any help is appreciated.