I've added a new function to my .vimrc for creating quickly a new task:

#+BEGIN_EXAMPLE
    function! CreateTask()
        let context = input("Enter context: ")
        exe ":set noautoindent"
        exe "normal 0"
        exe "normal o \<tab>- [@".context."]  "
        exe ":set autoindent"
        exe ":startinsert"
    endfunction
#+END_EXAMPLE

and then this mapping: =map ct <esc>:call CreateTask()<cr>=

Now, I've just to hit =,n= and type my context. A new line will be
inserted and I just have to create my task.