There have always (well, for a very long time) been two buildings. The Chinese-style builings you're referring to and -until 2009- an ugly concrete building. The Sinohotel page also shows parts of the former new building, the big atrium buffet restaurant. The old building is connected to a new one, and as far as I remember houses the club lounge and rooms.
The new part (the ugly concrete building you see on the sinohotel page) has been torn down. The new building you see on the CP page has been at this spot since 2009.
Afaik (stayed in 2010), the Chinese style buildings and gardens are still there. On the CP welcome page, you can see a very small part of the old buildings on the third picture, right to the car park.

However, I'm also surprised that the official CP page doesn't show any photos of the Chinese gardens and Chinese-style building. Could be that these will be replaced at the next building stage. A shame, indeed.