yeah, I just tried that too. will change it from init.pre to v310.pre after work and check again. BUT for me spamassassin --lint does work, end without an error and the sample tests catch the spam so it seems to be working :-(
the only concern I have is that after amavis-new stop and amavis-new debug-sa the process seems to 'hang' when attempting to create the Berkeley DB and jsut hangs but when I start it again, amavis-new start all is good, no errors and just works...
I guess your problem is that spamassassin doesn't seem to be in the default path, so try a which spamassassin and run it from taht location? aka /your/path/to/sa --lint ?