I am using Social Framework to post to WeiBo but i couldn't find WeiBo under phone's setting. I only found facebook and twitter. Any idea how to enable WeiBo on your device?
You need to enable the Chinese keyboard in the Settings app. Specifically:
Settings -> General -> Keyboard -> International Keyboards -> Add New Keyboard...
There are a number of Chinese options, I believe any of them should work but please correct me if I'm wrong.