As you already know, opera mini 3 and opera mini 4 beta have trouble to create post on blogger.
To post on blogger, just do this.
-from PC, login to your blogger and look for yourblog id on the address bar
-Run opera mini 3
-create new bookmark
replace "yourblogid" with your blog id :D
-save the bookmark.
-open that bookmark.
login and set to remember, and open that bookmark again.
Now because you are logged in and set to remember. You only need to open that bookmark everytime you want to creat new post on the go.
Happy mobile blogging!
this guide typed and posted using opera mini 3.