Hai Mauricio,

Your have to setting at settings-> General-> composer-> composer settings-> composer Editor-> select built in- EasyBlog composer,

To insert a block into a post there were an icon name add block at above left side you composer and you select any of the item and put inside you composer.

see my video for more understanding:-

http://screencast.com/t/IrjULS0Xg

Hope this help.