Procurement Schedule Weights

Hi All,

I am presently working on preparation of overall EPC schedule. I want to add weights to procurement activities like:

. PO Placement

. Vendor doc. approval

. Manufacturing

. Inspection

. Ex Works

I can calculate weights as per total equipment cost but how to put this in primavera and then measure procuremrnt progress in order to get the S- curve for plan Vs Actual.

Please suggest how to proceed.