hmm, after thinking a second, I found work-around to get "Tenuki" text:
* Do not put tenuki-move into SGF.
* Enable "missing move" exceptions in Board options -> Detailed Exception Options for diagrams.
* Alter English translation for "missing move" exception to "Tenuki".
Translation editing is documented in web (http://gowrite.net/help/en/tech/translation.html
); you should alter EXCEPTION_MOVE_MISSING -named string in SgfText.
As missing move exception is not normally used in diagrams anyway, this should not make any