The Clasmerdon was part of the Black Ball fleet and 6 ships sailed from Aug 1854 from Liverpool for Oz - Marco Polo, Clasmerdon, Constance, Champion of the Seas, David Mcivor and Indian Queen, arriving late 1854/early 1855.
Passenger records for the journeys by the Constance, Champion of the Seas and Indian Queen - nowt for Marco Polo, Clasmerdon or David Mcivor - are available at the site you have been referred to.
As advised, the record you are after doesn't appear to have survived.
Note - the Marco Polo has a record for its Oct 1855 arrival.