Does this only work on the Pro version? I tried adding a Groovy script before the HTTP Test Request step and also tried moving it to afterwards and I still get that line in the request. Also, how can I add "Content-Type: application/xml" below "Content-Disposition"?
When that didn't work, as a workaround I tried post all the actual characters for the body including the form parts and manually added the "Content-Type". It seems that soapUI parses the request body based on the media type in the drop down. My content ended up having the '\r's removed. It would be useful to have an option to paste in raw data so there is no parsing (at least for the body, maybe for headers as well).