Question about foreign arrays in LispWorks

Hi,

Is this the correct way to allocate (on the stack if possible) a
foreign array of ints and access it?  It seems to work okay in OpenMCL
and SBCL but it bombs with a bus error in LispWorks Personal 4.4 (on
OSX, I don't have other LispWorks platforms handy at the moment):

(defun array-test ()
  (with-foreign-object (a '(:array :int 5))
    (setf (deref-array a '(:array :int) 0) 666)
    (deref-array a '(:array :int) 0)))

James