Park domain using UAPI?

I've been searching through the UAPI documentation and I can not figure out how to park a domain (create alias apparently now). If I use cpapi2 --user=my_user Park park domain=example.com then I get " reason: This feature is not enabled" which I'll inquire about in another thread. I would highly prefer using the UAPI as I can very easily call is with PHP's shell_exec.