Filling in missing dates using a linq group by date query

Question

I have a Linq query that basically counts how many entries were created on a particular day, which is done by grouping by year, month, day. The problem is that because some days won't have any entries I need to back fill those missing "calendar days" with an entry of 0 count. My guess is that this can probably be done with a Union or something, or maybe even some simple for loop to process the records after the query.

Here is the query:

from l in context.LoginToken
 where l.CreatedOn >= start && l.CreatedOn <= finish
 group l by
 new{l.CreatedOn.Year, l.CreatedOn.Month, l.CreatedOn.Day} into groups
 orderby groups.Key.Year , groups.Key.Month , groups.Key.Day
     select new StatsDateWithCount {
                                    Count = groups.Count(),
                                     Year =  groups.Key.Year,
                                    Month = groups.Key.Month,
                                      Day = groups.Key.Day
                                                                  }));

If I have data for 12/1 - 12/4/2009 like (simplified):

12/1/2009 20
12/2/2009 15
12/4/2009 16

I want an entry with 12/3/2009 0 added by code.

I know that in general this should be done in the DB using a denormalized table that you either populate with data or join to a calendar table, but my question is how would I accomplish this in code?
Can it be done in Linq? Should it be done in Linq?