Creating Error status code

Hi...
I want to create error statuscode for errors.....
to use it in web config file which redirects to custom error page in the case of generation that particular error....

example
web.config

<customErrors mode="On" defaultRedirect="Default2.aspx">

<error statusCode="20(my error statuscode)"

redirect="custom error page" />

</customErrors>

Are you talking about creating custom error messages in IIS ?

http://support.microsoft.com/kb/302570