XML : compile webex xml schema to java code using jaxb

I am trying to compile webex's xml schema to java code using jaxb. I found this project as a starting point:

https://code.google.com/archive/p/webex-java-sdk/

It compiled under java 8 with a few minor changes. My problem now is that I am getting an error result from webex:

"unable to instantiate com.webex.xmlapi.service.binding.CreateMeeting; java.lang.ClassNotFoundException: com.webex.xmlapi.service.binding.CreateMeeting"

I google it and found similar questions, like this one: Cisco Webex API Exception

The problem seems to be that I am not prepending the fully qualified class name in my xml document. I looked for ways to instruct JAXB to do so but couldn't find any.

Thanks.