finalize the action "Submit business process to API" (Post/XML)

It is necessary to refine the action "Submit business process to API" (Post/XML) in such a way that it is possible to send data in xml format in the body of the request transmitted by the post method, and also add the field "test request in xml format" to the action with a list of add. process fields from where to get the content for the request body. as a result, the action should take what is in this field, insert it into the request body and send it using the post method to the given address pricing and discussion here https://crm-onebox.com/ru/support/api-onebox/2278-popravit-rabotu-deystviya-quotperedat-biznes-protsess-v-apiquot-postxml/