How to use Bitaddress.org and Blockchain.info with Testnet coins?
In order to reach the testnet version of bitaddress you must append ?testnet=true to the url:

https://www.bitaddress.org/bitaddress.org-v2.9.3-SHA1-7d47ab312789b7b3c1792e4abdb8f2d95b726d64.html?testnet=true