I've used the Maps APIs many times before and not had this problem, but I've clearly done something wrong with this IntelliJ project. Under Settings->SDKs I have specified the platform 7 Google API in the classpath - it still fails to build saying the Maps APIs are not there. I have also tried added a separate reference to the classpath to the Google APIs .jar, but still the same problem.
How do I fix my IntelliJ IDE project so it correctly builds against the Google APIs?
It's been a long day, I am probably missing something obvious.