We are trying to set up the functionality mentioned above. 

We are aware of the reply to a similar inquiry placed 3 years ago (https://help.zoho.com/portal/en/community/topic/upload-a-file-or-document-with-support-api) - since nobody has responded to my question placed there I have decided to create a new topic on that. 

if it is still not possible, is there any chance to introduce such a desirable thing in the nearest future?  

Please kindly respond in a reasonable time. 

Best regards

Michal Pawlicki.