After some attempts, I finally managed to install the Mountain Lion on my 1340. The only issues, as was to be expected, is the icon battery and the sleep. But my battery is on the final lifetime and this functionality does not make me miss.
So, I resolved to test part this installation guide to install the Mavericks Developer Preview. For my surprise, works perfectly like the Mountain Lion. The inicial setup I do with myHack and the post install, using the step-by-step of post #1. The icon battery and sleep still not running!
Thanks for the help of everyone who contributed to this topic. And sorry for poor english!