open this link http://talk.weibo.com/ft/201205095378 then you will see as the picture. Click on the green button.
the page will change as the picture then click on the button in red circle as in the following picture
click on the button in red circle and write whatever you would like to ask him,
then click on green button
*Note1* the chat room will be on 9,May and start from 15.00-16.00 in local time (China)
*Note2* especially, you should be have weibo account before
hope you be enjoy, Good luck ^^
a great step-by-step! thanks for this!