Cost objects to PM order

Hi,

we have request from some external application to post cost all information about PM order with high level of detail. For some information we can use standard BAPI function f.e. like

BAPI_ALM_OPERATION_GET_DETAIL

BAPI_ALM_ORDER_GET_DETAIL

So we can post information about Costs, Notifications ....

BUT

we are not able to post information about all material documents and also materials in this documents and also information about invoices, which has connection to our PM order - we see only costs in order but we cannot see the particular items of invoice or purchase order....

Is any standard way how to get or we must create some special custom function for that?

Thanks

Petr