Item wise revenue while billing

 Hi Folks,

We have following requirement.

Cost calculation based on events, but revenue should be captured based on Item.

Ex:- Project 1 is having 2 tasks, task 1 is material based and task 2 service based, now we have created project expenditure for both task 1 and task 2 and costing calculated as expected, now billing is completion of work %. i.e 30 % completion get 50% amount (As per agreed terms and condition), but billing need to send for material related items in detail.

so please let me know how we can capture these details billing point of view.

Note:- We have Project costing, Billing and Project Manufacturing, Order Management, Service contracts, Receivables , so please provide your inputs to achieve this requirement other than customization.