Maybe it is an option for you to directly post the file as binary?
regards, Fabian
The only option I know of in this particular moment is using Form-Data:
4.3 Form-Data
This option allows you to generate a multipart/form-data request for multiple parts. Each part is a pair with a key and a value (microflow expression).
FileDocuments and images are are also supported for this option when used as variables in microflow expressions.
You can find it here: