Hate doing this, but 'me too'. I'm going to take a look at the source tomorrow, but if Dain or someone else that knows CMP2.x in JBoss 3 could take a look it would help a lot.
As long a you are not using Oracle, it will work. If you are using Oracle you can't have a CLOB > 2000 characters, because Oracle's JDBC drivers are broken/non-complient (even though they are certified). For normal databases just changed the jdbc-type to CLOB and sql-type to what every your database needs to create a CLOB column in a CREATE TABLE statement.