Need to Sort on this aggregate for Interactive Sort

I need to sort on this value =Last(Fields!ACTIVITYTIMESTAMP.Value) for an
Interactive Sort. You can't sort on aggregates, but I need to do that
because that is the information that is displayed in the report that I am
sorting on. If I sort by =Fields!ACTIVITYTIMESTAMP.Value it does not work.
Ideas?
BJtry puttiing it in the select statement, something like this
=Last(Fields!ACTIVITYTIMESTAMP.Value) as ACTIVITY
and then sort by ACTIVITY in the report
"bjkaledas" <bjkaledas@.discussions.microsoft.com> wrote in message
news:66FB0E3F-06B3-4D84-B0BA-73266FDCC0A1@.microsoft.com...
>I need to sort on this value =Last(Fields!ACTIVITYTIMESTAMP.Value) for an
> Interactive Sort. You can't sort on aggregates, but I need to do that
> because that is the information that is displayed in the report that I am
> sorting on. If I sort by =Fields!ACTIVITYTIMESTAMP.Value it does not
> work.
> Ideas?
> BJ