customErrors

Добрый день,

Имееться следующий web.config:
-------------------------------------------------------------------
<configuration>  
    <system.web>
        <customErrors mode="On" defaultRedirect="f.aspx">
        </customErrors> 
    </system.web>
</configuration>
-------------------------------------------------------------------
При возникновении ошибки (нет досупа к папки bin), все равно появляеться:

Server Error in '/webapp' Application.
--------------------------------------------------------------------------------
Runtime Error
Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed.
Details: To enable the details of this specific error message to be viewable on the local server machine, please create a <customErrors> tag within a "web.config" configuration file located in the root directory of the current web application. This <customErrors> tag should then have its "mode" attribute set to "RemoteOnly". To enable the details to be viewable on remote machines, please set "mode" to "Off".

<!-- Web.Config Configuration File -->
<configuration>
    <system.web>
        <customErrors mode="RemoteOnly"/>
    </system.web>
</configuration>
 
Notes: The current error page you are seeing can be replaced by a custom error page by modifying the "defaultRedirect" attribute of the application's <customErrors> configuration tag to point to a custom error page URL.

<!-- Web.Config Configuration File -->
<configuration>
    <system.web>
        <customErrors mode="On" defaultRedirect="mycustompage.htm"/>
    </system.web>
</configuration>
 
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Если в web.config  заменить defaultRedirect="f.aspx" на defaultRedirect="f..html", то при возникновении ошибки идет перенаправление на f.html. Почему не происходит перенаправление на *.aspx, а только на *.html?
Cпасибо за помощь