Revenue deferral function...

Hi,

    I'd like to understand how to use the revenue deferral function.

I gather that revenue deferrals can be applied for customers invoices with a preceding sales document and this is done using accrual methods identified in sales orders.

Now I'm not sure;

1) where in the sales order do we enter the accrual method.

2) how do we configure custom accrual methods.

The business scenario is that any revenue received during the course of the year should be spread across for the full year [accruals and deferrals].

Thanks

Puru