LEFT JOIN tables with EJBQL

Question

I am trying to join two EJB's using EJBQL (with an underlying MySQL data source). The two tables in question are

Machine
  - Hostname
  - ... unrelated fields ...

and

Location
 - Code
 - Human readable description

The tables should be LEFT joined on the location code and the first three characters of the machine's hostname. In straight up MySQL the command is:

SELECT * FROM machine m LEFT JOIN location l ON (SUBSTRING(m.`Name`, 1,3) = l.`Code`);

When I put a similar thing into EJBQL I get all sorts of errors raning from null poninter exceptions to invalid syntax exceptions -- here's what I have tried:

query="SELECT NEW someObj(m, loc) FROM Machine as m " +
      "LEFT JOIN FETCH Location as loc " +
      "WHERE (SUBSTRING(m.hostname, 1, :length) = loc.code)"

I've also tried using "ON" instead of "WHERE" -- but EJBQL comes back with an unexpected keyword when I use ON...

So -- has anyone succeeded in doing something like this before? The documentation for EJBQL seems to indicate that LEFT join is OK, so I'm not sure what the deal is...

Thanks

---

Edit: The exception I am getting is:

outer or full join must be followed by path expression -- it was buried in the same line as the null pointer deal

Edit 2:

There is no relation between a Machine and a Location, unfortunately I cannot change that