How can we generate One invoice with FOB and C&F values

Dear All,

Valuable suggestion required for below business process

Two different invoice to be generated one with FOB Value and another with C&F Value.

1.FOB invoice includes  -Gross Price +Freight Charges -Discounts = Net Value of the Invoice

2.C&F invoice - By adding both the Freight Charges and discount values,the price of each material price to be increased

   and net value should be same as per the FOB invoice.

Firstly will be generating FOB invoice output,and by adding the values of Dicounts/Freights will generate C&F invoice

Please suggest how can we accomodate both the above possibilities for 1 customer and 1 document type.

How can the values distributed to each line item in and how can both net values managed to get same value

Thanks & Regards,

Kumar Babu,