Below I have included the email address to the great folks at the Certification Team for all SolidWorks Certification Exams. I have worked with them in the past for my own questions about various Certifications. I am very sure they can help you with this matter.
In my case, my SolidWorks professor actually provided us with a code and detailed instructions as an alternate to the final exam. She was in contact with SW (or the schools VAR) who helped set everything up. We just came In, followed the provided instructions to the correct website and entered the code. Then we took the test.
At work I have contacted the certification team noted above and they are very helpful in assisting you if you school/professor does not provide the information.