How to set EXCEL XML Publisher Template for Backward Compatibility?

For RTF templates within Word, you can do this from the BI Publisher Options in the Build Tab. For Excel, this same option does not exist. And main reason why I am looking for this is because using XDOXSLT commands in a True Excel template is throwing: oracle.xdo.parser.v2.XPathException: Extension function error: Class not found 'oracle.xdo.template.rtf.XSLTFunctions'. I had found a hit on this topic which suggested that XML Publisher needs to be run in backward compatibility mode due to some features version 12 is passing.