The version 1.8 does not support post,

Hm, for me posts, pages, and custom post types all work.

Are posts not showing up in the dialog where you choose which page or post to insert, or are posts not showing up when rendered on a page?

Also, have you modified the “post” post type in your theme anywhere?
http://codex.ww.wp.xz.cn/Function_Reference/add_post_type_support