I know your feeling. I have a similar problem with brazilian customs and postal service. Don’t know if things in China are worst than Brazil, but here everything is too expensive and slow to import (and sometimes, a package “disappears”). I always try to buy using Fedex, DHL and UPS. It is super expensive, but very fast and secure.
Can’t you find a steinberg key in a chinese shop? I bought my first key (included with Cubase 6) many years ago from a local shop (official brazilian reseller at the time).
Here is the official distributors (maybe they will help you):
China
YAMAHA MUSIC & ELECTRONICS (CHINA) CO., LTD
2F, Yunhe Building, NO.1818 Xinzha Road,
Jing An District, Shanghai
200042 P.R. CHINA
www.yamaha.com.cn
China (Macau & Hongkong)
TOM LEE MUSIC CO., LTD.
11/F., Silvercord Tower 1,
30 Canton Road
Tsimshatsui, Kowloon
Hong Kong
Taiwan
YAMAHA Music & Electronics Taiwan Co., Ltd.
2F., No.1, Yuandong Rd., Banqiao Dist.,
New Taipei City 22063,
Taiwan (R.O.C.)
TEL：(02) 7741-8888
FAX：(02) 7739-5558
website: http://tw.yamaha.com