Reporting Services runningValue

I am trying to use the sql reporting services and I cannot figure out how to use scope parameters
I created a report with various information about stores
If a grouping is specified, the running value is reset when the group expression changes.
I have a Group on =Fields!FECHA.Value in the dataset, and I want reset the field!Cost when Field!Fecha change
How change this expressions RunningValue(Fields!Cost.Value, Sum, Nothing) ?
Thank’s
Yovanny Vasquez
User group name, example "GroupDate"
Yovanny Vasquez
"yovys" wrote:

> I am trying to use the sql reporting services and I cannot figure out how to use scope parameters
> I created a report with various information about stores
> If a grouping is specified, the running value is reset when the group expression changes.
> I have a Group on =Fields!FECHA.Value in the dataset, and I want reset the field!Cost when Field!Fecha change
> How change this expressions RunningValue(Fields!Cost.Value, Sum, Nothing) ?
>
> Thank’s
> --
> Yovanny Vasquez