Invoice Matching - Multiple invoices to one receipt

 Dear All,

Can any one please help me on how to map the below mentioned scenario in purchasing and payables:

My purchase order consists of two lines : one for a server and another for consultancy fees.

My payment terms are as follows:

10% prepayment

20% on Order of server

50% on receipt of server

20% on installation of server.

The supplier gives me a proforma invoice for the prepayment, and then normal invoices as per the payment terms mentioned above.

As a company policy, we always match invoice to receipt.

How can i perform this transaction using purchasing and payables?

Kindly help