Seems like they're gonna allow withdrawals for altcoins after Chinese Newyear, they just posted this on their Weibo (Google translated):

最近让用户担心了，我们将在春节后首先安排人民币以及美元的提现工作，届时用户可以登录验证后提取账户中的余额。其他虚拟币的提现工作将在确保数字钱包安全的情况下陆续开通。首批开通提现的虚拟币将包括NXT，XCP，XTC等。

"Recently allows users worry, we will first arrange withdrawals work renminbi and the dollar after the Spring Festival, then the user can log on after the extraction verify account balances. Withdraw the work of other virtual currency will be opened in ensuring the safety of the digital wallet. The first opening of a virtual currency withdrawals will include NXT, XCP, XTC, etc."