The following in my ~/.xemacs/init-for-acl.el (requires using
~shapiro/.xemacs in your home dir):

(defun run-acl ()
  "Starts up the Allegro-CL/Emacs interface with composer"
  (setq fi:common-lisp-image-name (acl-location "composer"))
  (interactive)
(fi:common-lisp fi:common-lisp-buffer-name
                  fi:common-lisp-directory
                  fi:common-lisp-image-name
                  fi:common-lisp-image-arguments
                  fi:common-lisp-host
                  fi:common-lisp-image-file))

and in my ~/.xemacs/custom.el to map 'M-x run-acl' to the F8 key:

(global-set-key 'f8 'run-acl)