Index: sbbs.el
==================================================================
--- sbbs.el
+++ sbbs.el
@@ -698,11 +698,11 @@
 (defun sbbs-compose-create (vip)
   "Upload response or thread to board.
 If VIP is non-nil (or when invoked with a prefix argument), mark
 the post as \"VIP\", ie. don't bump the thread."
   (interactive "P")
-  (when (and vip sbbs--thread-id)
+  (when (and vip (not sbbs--thread-id))
     (user-error "A new thread cannot be VIP"))
   (let ((board sbbs--board)
         (url-request-method "POST")
         (url-request-extra-headers
          '(("Content-Type" . "application/x-www-form-urlencoded")))
@@ -709,11 +709,11 @@
         (url-request-data
          (url-build-query-string
           `((epistula ,(buffer-string))
             (ornamentum "") (name "") (message "")
             (frontpage ,(if sbbs--thread-id "true" "false"))
-            (vip ,(if vip "true" "false"))
+            ,(if vip `(vip "on") nil)
             . ,(and (not sbbs--thread-id)
                     `((titulus ,(read-string "Headline: ")))))))
         (url (if sbbs--thread-id
                  (sbbs--board-url (format "%d/post" sbbs--thread-id))
                (sbbs--board-url "/post"))))