How to load a pinyin.vim keymap in vim on Mavericks?

Question

I am trying to get this pinyin keymap to load into vim.

I have placed this file into ~/.vim/keymap/pinyin.vim.

Questions

1. How do I load this file automatically through a command in ~/.vimrc?
2. How do I turn this mode on/off?
3. How do I actually invoke these keymappings?

Answer

FDinoff's suggestion below is perfect. What I did on Mavericks was update to Snapshot 73 Vim 7.4.258, mv the old vim to /tmp and mv mvim to /usr/bin/mvim, create a symbolic link and I was all set.

Answer 1

This file is already part of the vim runtime so you don't need to include it yourself.

You can change what keymap you are using by using set keymap=pinyin. You can turn it off with set keymap=

To invoke the key mappings just type them literally in insert mode.

So for example typing a2 will get you á

Take a look at :h keycap (Note this feature requires vim has been compiled with the keymap feature)