It's really easy:
Just install from market SuperSU and it will work.
After rooting the tablet I got rid of most of the default app and garbage put in by the vendor, after a backup with titanium.
With terminal emulator I managed to dump the recovery partition
dd if=/dev/mtd/mtd3 of=/sdcard/recovery.img
And here is what Recovery builder did to it:
I'm still not sure if it will work, will post how it goes.