Hi Remshith,
The technique in Jamie's blog above involves using a formula. If you wish to create a chart or a group, this will not work unfortunately.
Here's one workaround that uses a Command Object:
Missing Dates in your Report? Create them in a Command Object
Another workaround is to use a 'lookup' table that has all possible dates (no gaps). You can ask your DBA to create such a table if it's feasible. You would then Join it to the existing table with a Left Outer Join on the Date fields.
Now, in the report, wherever you use the Date field from the existing table change it to use the Date field from the Lookup table. This includes Groups, Record Selection formula etc.
-Abhilash