I find a way to update office 2013 rt but not via dism.
unzip these cab files to get several msp files.
I create a script bat file that will be ran manually after deploy image on tablet.
"for %%i in (*.msp) do start /wait %%i /quiet /norestart"
And it will update office 2013 rt...
Thank you for your tools, and I want integrate office 13 rt updates into wim file, but I can't download these updates from microsoft website, could you sent me downloadable links of these updates? Thanks a lot!