ATP check in Mobile sales order

Team,

We have implemented an native mobile app using SMP and SAP CRM as back end system.

We would like to implement sales order creation from mobile app in online and offline mode. We are having one issue where sales order replicated from mobile app to SAP CRM do not carry out ATP check for items in order.

Would like to know if it's standard behavior or we need to do something to activate ATP check in mobile sales orders. How it works with standard mobile solution ?

Any pointers in this area will be appreciated.

Thanks,

Anagha