I'm using Oracle Content and Experience for document management.. and their API requires a multipart to upload files
REST API for Documents (0 Bytes)
I was using utl_http and it was a bit more involved than I would like, so I want to switch to use Apex_Web_Service.
The issue that I seem to be having is that the "boundary" in the generated request doesn't match exactly with the one generated in the body
header

body

You'll notice in the header that the boundary does not have the leading "-".. but if you check the API reference, it does.. this seems to matter.
Would this be a bug? Is there a way to specify the boundary? I don't see any options in the docs
Thanks,
Scott