IDocs for sending planned orders from APO to MES

Hi,

I need to understand how planned orders can be sent to an external MES system using IDocs. There is lot of information for integration using IDocs for ECC related objects, however didn't find any information on how to integration APO using IDocs with an external system (non ERP).

I need to understand the technical details like how to trigger an IDoc for planned order.

Also any information on Idocs in APO would be really helpful.

Thanks in advance for helping out on this topic.

Regards

Gaurav