Add a row after Total row in ALV report

Hi Experts,

I have a report is displayed by ALV format(not use function module to display it but use Class cl_gui_custom_container),I want to add a row after the total row. for example,

Customer amount1 amount2 amount3

10000 1,234 1,000 2,000

10001 4,000 2,000 1,000

10002 1,300 1,000 3,000

11000 1,200 4,000 3,000

Total: 7,734 8,000 9,000

Ratio% 31.27 32.34 36.39

the row of 'Total' is calculated by fieldcat-do_sum = 'X' But after the Total row we need a Ratio row to display the ratio. Yes we can calculate the total amout and ratio and then append it into the output itab, but we don't like this solution.We want to keep the total function in the ALV report.Any experts can poit me a direction. Thanks in advance.

Joe