J,
Thanks, the loadPackage did the trick (evm6670l in my case).
At first it could not find the headers as you say, but then I checked the MCSDK PDK TMS3206670 in the RTSC tab of the Properties. It then found the headers and I had thought this effectively included that functionality in my project. I guess there's a lot more to it. It's all a bit confusing at the moment.
Thanks,
Dave