Unable to post files with different content types and names

[salungh]

I'm trying to post two files that corresponds to a part of one message with content-type application/xml and bodytext/plain. In postman I go to form data POST and give the key=metadata and value=file1 path (xml) and Key=0 and value=file2 path(txt) and it works fine and I'm able to insert. I'm supposed to use the same name for the files while inserting i.e. metadata and 0 respectively. This is what I have done through robot to imitate this behavior and it always returns a 500 Internal server error.
Insert Data
${auth}= Create List ${ID} ${SECRET}
${params}= Create Dictionary Key=${value} app=${apps}
${headers}= Create Dictionary Content-Type=multipart/form-data
Create Session mysession ${URL} auth=${auth} max_retries=10 backoff_factor=0.2
${metadata}= get binary file ${CURDIR}${/}insert.xml
${0}= get binary file ${CURDIR}${/}messageInsertion1.txt
${fileParts} create dictionary file1=${metadata} file2=${0}
${resp}= Post Request retain /messages params=${params} headers=${headers} files=${fileParts}
Response Code Should Be Success ${resp}