It is still a secret feature (perhaps time to release it to the public, Igor?) but: yes, James. The handling of SDLPPX packages is completely transparent now.
I'd advise you to just open the package as a whole. There's no need to actually use the embedded TM: you can just close it. When you choose Project > Convert > Package, you'll get two options to pack: SDLPPX (again, e.g. for sending it to a reviewer, who hasn't Studio) or SDLRPX.
But hey, this is still secret.