Running Total in Details Section

Hi,
I have an invoice with details section and no groups. I want to show the running total of the positions at the bottom of the page and on each page. Where do I have to place the running total field?
thank you
sorinHave you tried the page footer...?|||Yes, the running total is wrong, it adds the value of the first postion from the next page. It should only show the sum of the positions shown on one page.

If I place the running total in the details section, its value is right, but then the running total is shown for each record, I want it only one time at the end of the details section.|||I don't think I've ever put a running total in a page footer, so don't know about it picking up the next record's value too.
One way would be to create your own formulas to do the summing. e.g.

1) In the details, suppressed
whileprintingrecords;
numbervar total;
total := total + {table.position};

2) In the page footer
whileprintingrecords;
numbervar total|||it works, thank you