Data Posting using ODATA

our Requirement is to Post  Dynamics NAV sales and Purchase data without using the Microsoft Dynamics NAV Windows client or the Microsoft Dynamics NAV Web client, Can It be Done by ODATa ?  I understand It Can not be done ,

We have to write CU using AL create and create SOAP service then only we can post data without using Windows client or the Microsoft Dynamics NAV Web client,

But I need Expert Confirmation .

Thanks 

Anju