How can create individual wallet for each user

[Bitcoin]

How can create individual wallet for each user

I am going to develop an exchange website in PHP something like http://coinbase.com,
Now, I have setup the http://bitcoindevkit.com/ for it and its running fine generating new addresses in the same wallet,
but now I need to create a individual wallet for each user, so how can create individual wallet for each user and then I can able to create address on that wallet.

Source: How can create individual wallet for each user