Thank you very much!. I tried to modify the UrlRewriting.config file, but this does not work, and the part that should change is:

That's the change I want to get

Thank you very much!

I have hardly any expertise in UrlRewriting.NET that's shipped with Umbraco since I prefer IIS Url Rewriting module.

For IIS Url Rewriting module the configuration might look like this:

        <rewrite>
            <rules>
                <rule name="ASPX to HTML">
                    <match url="(.*)\.html" />
                    <action type="Rewrite" url="{r:1}.aspx" />
                </rule>
            </rules>
            <outboundRules>
                <rule name="HTML to ASPX">
                    <match filterByTags="A" pattern="(.*)\.aspx" />
                    <action type="Rewrite" value="{r:1}.html" />
                </rule>
            </outboundRules>
        </rewrite>

Thank you!. I placed the code I put in the file "/config/UrlRewriting.config" but I did not work and has launched a mistake, I'm using Umbraco version 4.7.1. Any other ideas?

Nope. The ~/config/Urlrewriting.config is for UrlRewriting.Net. The snippet I gave is for the IIS URL rewriting module. You need to install it if it's not installed already. The download link: http://www.iis.net/download/urlrewrite. And than put that <rewrite> section under  the <system.webServer> one. Also after installing the URL Rewrite module you can use IIS manager to maintain the rules with GUI.

Thank you!. I installed UrlRewriting in IIS 7, Also do I have added a rule:

Where do I put this code?  <rewrite>

            <rules>
                <rulename="ASPX to HTML">
                    <matchurl="(.*)\.html"/>
                    <actiontype="Rewrite"url="{r:1}.aspx"/>
                </rule>
            </rules>
            <outboundRules>
                <rulename="HTML to ASPX">
                    <matchfilterByTags="A"pattern="(.*)\.aspx"/>
                    <actiontype="Rewrite"value="{r:1}.html"/>
                </rule>
            </outboundRules>
        </rewrite>

This code is the configuration for the Url Rewrite IIS module and should go into web.config (to inside <system.webServer> section). If everything after that is ok you will see this couple of rules (one inbound and one outbound) when you open the "Url Rewriting" settings in the IIS Manager (this setting editor window is in fact just GUI to this config section). You can also try just to add this rules from the GUI istead of putting them down into the web.config file manually.

Thank you for helping me!. I think it will not be long for this to work, look at the pictures:

I feel I lack little to solve my problem. To what may be this error?

Woops. "rulename" -> "rule name" (with a space :-)

I'm sorry, the last error was showing syntax, see the pictures:

I feel I lack little to solve this problem. Thank you very much!

Here's exactly how I've configured in my config:

        <rewrite>
            <rules>
                <rule name="Html to Aspx">
                    <match url="(.*)\.html" />
                    <action type="Rewrite" url="{R:1}.aspx" />
                </rule>
            </rules>
            <outboundRules>
                <rule name="Aspx to Html">
                    <match filterByTags="A" pattern="(.*)\.aspx" />
                    <conditions logicalGrouping="MatchAll" trackAllCaptures="true" />
                    <action type="Rewrite" value="{R:1}.html" />
                </rule>
            </outboundRules>
        </rewrite>

is working on a reply...