How to allow detailed Error for .net applications & Other applications (ASP, HTML) in IS7 + IS8

*through the configuration files (web.config) 

Web.config file configuration for error code correction

For ASPX files

<system.web>
<customErrors mode="On" defaultRedirect="404.aspx">
	    <error statusCode="404" redirect="404.aspx"/>
	</customErrors>

.........

For another files error like html, asp, htm another’s

<system.webServer>
<httpErrors errorMode="Custom" existingResponse="Replace">
                <remove statusCode="404" subStatusCode="-1" />
                <error statusCode="404" prefixLanguageFilePath="" path="/404.aspx" responseMode="ExecuteURL" />
            </httpErrors>

.............