Since Comtrend 5813 isn't supported, I have collected some info and added it to the wiki.
I guess a proper patch for board id 96369R-1231N has to be added in order to support it, but since I have little experience in linux developing I prefer that someone else shares some of his/her wisdom .
http://wiki.openwrt.org/toh/comtrend/ct5813
Greetings!