Hi Ruslany,
thanks very much for your quick reply. Maybe my conditions were wrong, they were inspired from:
http://blogs.iis.net/carlosag/archive/2008/09/02/iis-7-0-and-url-rewrite-make-your-web-site-seo.aspx
Here's what I was using:
<rule name="Redirect Old Files and Broken Links" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{OldFiles:{REQUEST_URI}}" pattern="(.+)" />
</conditions>
<action type="Redirect" url="{C:0}" />
</rule>
</rules>
<rewriteMaps>
<rewriteMap name="OldFiles">
<add key="/The+first+page+name+.aspx" value="/folder/47-the-page-name" />
<add key="/The+second+page+name+.aspx" value="/folder/48-the-page-name" />
</rewriteMap>
</rewriteMaps>