By default, the public service pub.string:base64Encode inserts a new line after 76 characters of data. This is not the canonical lexical form expected by MTOM implementations. If you use this public service rather than a custom service for base64 encoding, you can use the optional input parameter useNewLine to remove the line break and the optional input parameter encoding to change the encoding. The default value for useNewLine is true, which keeps the line break at 76 characters. If you do not specify the encoding, ASCII will be used.

If you use the public service pub.string:base64Decode for base64 decoding, you can use the optional input parameter encoding to change the encoding. If you do not specify the encoding, ASCII will be used.