Custom time characteristics

Hi !

I've a problem in the presentation of a report : I need to display some key figures every decade (10 days). These Key figures are given every day. But the possibilities of time characteristics choices are limited : I can only display every day (0CALDAY), or every week (0CALWEEK), evey month (0CALMONTH)... nothing for the decade.

It's not possible to create time characteristics. Is there any other solution ?

Thanks,

Étienne