lispworks com/automation how to construct a byte-array(non-unicode)

Hi,guys,i want to invoke com method of IWebBrowser2::Navigate with the PostData parameter,where the PostData should be a byte-array.
(setq PostData  #(123 122 111))
(com:invoke-dispatch-method 
   (top-htmleditor-pane-dispatch self)
   "Navigate" url nil nil PostData)
but when i print PostData where event "BeforeNavigate2",it becomes:
#(3 0 0 0  0 0 0 0 123 0 0 0  0 0 0 0 111 0 0 0   0 0 0 0)
I have tried to construct PostData with make-array :element-type '(unsigned char 8) and
make-lisp-variant '(:array unsigned :char) etc.but the problem still exists.
how can i fix it??
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With best regards,jingtao.
2009-12-12