My report group does not group. Please help

[Maine]

Can you help me with this one please?

I have a table on my report that has 2 groups.

The query feeding this table is returning 8 records like this: money-type, volume1, volume2, rate1, volume3, volume4, rate2, percentage

The first and relevant (for my Q) group should help me calculate the sum of volume1 of all the records of the same money-type (USD or EUR or...) so I created a group "val_grp" in the dataset that is feeding this table with the group expression $F{valsrt} 

This should be very simple. However the variable that should calculate the sum (defined with Calculation: Sum, Reset type: Group, Reset group: val_grp, Increment type: None, Variable expression: $F{volume1}) does NOT calculate anything. It just returns the latest value of volume1.

I have previoulsy built this report not using a table and this same way of crouping and calculating worked just fine. In this version, using a table, though..........it WILL NOT WORK!! Does anybody have a brilliant idea for me?? This is my first time using a table in ireport. Does grouping in tables work differently?

Thanks in advance.