Hii Rajkumr,
The complete scenario may not happen In APO, as SNP heuristics and optimizer do not support MTO.
Find the attachment for the same.
http://help.sap.com/saphelp_SCM700_ehp02/helpdata/en/4c/c749c0d43f6a4ae10000000a42189c/frameset.htm
well the alternative way is :
Alternative 1:
You can use CTM for MTO scenarios CTM supports both PIR and sales orders.
Because any way you need requirement for raw materials for planning in advance.
Alternative 2:
Put manual Pur req well in advance for raw materials. and you can plan in ECC or in APO, no issue.
And put the requirement as sales order for FG in the DC or MFG plant. When the dependent requirement will created for Raw materials, it will consume from the manual PRs.
Regards
Debashis