Calculating Field sum over multiple pages

Hey all,

i seriously need the help of the adobe community - your help! Id like to calculate the fieldsum of multiple fields in a grand total field. My problem is that the subfields are on more than one page, therefore i was trying to use a for loop to get all my subtotals in the whole document and sum them in the grandtotal. But that not working for me, any suggestions would be great. Right now im using this piece of code :

for (var nPageCount = 0; nPageCount < xfa.host.numPages; nPageCount++)

{

var fields = xfa.layout.pageContent(nPageCount , "field", 0);

var total = 0;

for (var i = 0; i <= fields.length-1; i++) {

     if (fields.item(i).name == "Positionspreis") {

         total = total + fields.item(i).rawValue;

     }

}

this.rawValue = total;   

}

Any help would be great!

BR