InfoPath Dev

I have a repeating table in my form and there is a 'total' column. Further down the form (not in the repeating table though) i have a total field and when the totals are updated in the repeating table i want the total field at the bottom of the form to update with the final price but its just not updating at all. How can i caluclate the  total of the column? (i have tried using the sum() function

thanks

 Are you using a calculated default value for the field? Is the checkbox selected to update it when other fields change? The sum() function is meant for this...See attached sample - save it locally, right click and select design to open.

Hi - yes, the field in the repeating table that i need to total up is a calculated value and updates when field is changed. also the field that should show the total is a calculated value with the sum function and this is set to update when changed. Will have a look at the sample, thank you