REST API xml data instead json

The REST API is designed around JSON so calling it with XML is impossible.

What is your use-case?

Customer have application bus which will send xml for create data in table 1IM. 

Option one, use the One Identity Manager SOAP service, which is based on XML, but be aware that this one might go away in the future.
Option two, write your own web service that accepts the XML payload as defined by your application bus as the data transformation and mapping into the One Identity Manager objects and properties have to be done anyways.

Thanks!