Download and install WinRAR:
http://www.rarlab.com/rar/wrar500.exe
Download iTools:
http://itools.cn/multi_lang_pc_download.htm
Then download the BBM ipa file:
http://qzal.net/01/2013-08/6cfd2d57601.zip
Plug in your iPhone
Now open iTools, go to your apps on your phone and click install (top right)
select the BBM ipa file you just downloaded.
When you open the app it will ask for apple id etc...
use : username - L777n@live.nl
password - Ss123456 (case sensitive)