Milestone Payments

Hi,

I'm not sure if this is possible in AR or not, but hopefully someone can point me in the right direction.

I have a requirement to request payments for AR invoices based on specific milestones rather than installments by days/date.  The AR invoices are related to charges for building works and we would like to request payment when certain stages are completed.  In my basic scenario, we would have an invoice for £100K, of which 10% is due when the foundations are laid and 20% when the roof is on etc.

These invoices are being interfaced to AR, so my options are to configure something in AR to match the above requirements or to have the third party software generate individual invoices based on when the stages are complete rather than send over one invoice.