Internal orders to WBS Element

Hi,

I,m working in a Project System implementation project, where all other modules are already in use.As per the existing process, Internal orders are created for asset accounting.Those are of statistical. All the purchase orders & costs are booked referring to the internal orders, the same cost is directly settled to Asset Under Construction or Asset.As the internal orders are created as statistical, there is no seperate settlement process & all the costs are directly settled either in AUC or in Asset as & when they are incurred(posted).

Now as we are implementing Project Systems, Internal orders are going to be replaced by WBS Elements. Customer requirement is the same process of online settlement of costs to Assets from WBS Element & he doen't want to settle seperately.

Now the issue is, 1) how the process can be mapped in SAP?

I feel creating the WBS elements as statistical, the same process can be mapped. Is it possible/

2) As one project is already in progress & some postings have been taken place against internal orders, customer wants to see all those postings on new WBS element, now how to migrate the same to respective WBS element in the new system?

Thanks

Kishore