the "org.hibernate.sql.OracleJoinFragment.addLeftOuterJoinCondition"
does not take the "!=" operator into account.

it places the "" like this "!=" instead of " !="
( != is a valid operator for Oracle )
and it returns <> for the '<>' operator

here's a patch. (maybe not the best one )
/**

• This method is a bit of a hack, and assumes
  * that the column on the "right" side of the
  * join appears on the "left" side of the
  * operator, which is extremely wierd if this
  * was a normal join condition, but is natural
  * for a filter.
  */
  private void addLeftOuterJoinCondition(String on) {
  StringBuffer buf = new StringBuffer( on );
  for ( int i = 0; i < buf.length(); i++ ) {
  char character = buf.charAt( i );
  boolean isInsertPoint = OPERATORS.contains( new Character( character ) ) ||
  ( character == ' ' && buf.length() > i + 3 && "is ".equals( buf.substring( i + 1, i + 4 ) ) ) ;

if( character == '<' && buf.length() > i + 1 && ">".equals( buf.substring( i + 1, i + 2 ) ) ){
isInsertPoint = false;
buf.insert( i, "" );
i += 3 + 2;
}

if ( isInsertPoint ) {
buf.insert( i, "" );
i += 3;
}
if( character == '!' && buf.length() > i + 1 && "=".equals( buf.substring( i + 1, i + 2 ) ) ){
buf.insert( i, "" );
i += 3 + 2;
}
}
addCondition( buf.toString() );
}