If you want to know what other people use to do this here I come:
How I make the ext partition:
Minitool partition wizard (windows)
Clockwork 6.0 (only for CM10+)
I didn't have any trouble with that programs, but be careful with the Clockwork because formats ALL the SD card, the ext and the fat partition, so make sure you do a backup of the SD.
Format of the second partition:
Link2sd is the best, other caused troubles over the time (reboots, not reading the sd, not reading the ext partition, etc)