LINQ group by date - include empty days WITHOUT using join

Using C#, NHibernate, NHibernate to LINQ. Using NHibernate to LINQ, I do not have the JOIN functionality. I can not use QueryOver either.

I have a LINQ query that counts the amount of Leads and Sales. This table only creates when a new lead or sale is done, so some days there is no row inserted. Doing the following query works

var query3 = query2.AsEnumerable()
             .Where(x => x.Created <= toDate.Value && x.Created >= fromDate.Value)
             .GroupBy(x => x.Created.Date)
             .Select(g => new ReferrerChart {
                 Date = g.Key.Date,
                 LeadsCount = g.Count(x => !x.IsSale),
                 SalesCount = g.Count(x => x.IsSale)
             });

but some dates are not in there (the dates there were 0 leads and sales).

How can I include these dates and let them set LeadsCount = 0 and SalesCount = 0 WITHOUT using join?