Hi Brad - yes the API should certainly work during the trial. When you use the link above, if you use the exact same user credentials to login, it should work just fine. But a couple words of caution:
(1) Better to not use your email. Use your User Name instead.
(2) Don't put anything in the SessionID in this case. Either you would use a Password, or a SessionID. In the simpliest of examples, the password is desired.
HTHs,
Paul