Hi Chetan,
It's always better to use the CRM_ORDER_MAINTAIN as mentioned by Praveen. But how many activities you will create using the Report program ? Incase of multiple creation, please make sure that you call the One Order API only once after populating all the data.
I think that since the data model has been enhanced by AET, these fields will be present as a part of the One Order Data model. So, you can easily populate these structures with the values and API will take care of the rest.
Be cautious about using the One Order API and use it by ensuring that proper performance guidelines are maintained.
Hope this helps.
Best Regards,
Samantak.