WordPress - Domain and Blog mapping

Question

Hi,

Can any one help me on this. I have a word press blog and i registered a domain with wordpress and mapped that domain with my blog.

When i give the registered domain name it redirects me to my blog address only but not showing the blog within the domain name. Can any one suggest me on how to do that.

For your reference,
My Blog is KarthikeyanAnbarasan.Wordpress.com
My registered Domain is f5debug.net

When we give f5debug.net in the address bar of the browser it redirects to KarthikeyanAnbarasan.Wordpress.com
and shows the address as KarthikeyanAnbarasan.Wordpress.com in the address bar. But it should show f5debug.net

Pls help me on this.

Thanks
Karthik