Aderson,
Per your advice added 'advanced' between the previously empty quotes as shown below. Appears to have worked just fine (no aspx extensions). I say appears as I am not aware of what other functionality my be related and not working with this simple change. But for now good.
I don't have a clue however why the default 404 page not found functionality does not get applied when you upgrade to 7.1 from 7.x. That would be very nice. Any clues? Makes me worry about fundamental changes between editions, especially with all the Evoque stuff going on.
<add name="DNNFriendlyUrl" type="DotNetNuke.Services.Url.FriendlyUrl.DNNFriendlyUrlProvider, DotNetNuke.HttpModules" includePageName="true" regexMatch="[^a-zA-Z0-9 _-]" urlFormat="advanced" />
</providers>
</friendlyUrl>
<caching defaultProvider="FileBasedCachingProvider">
<providers>
<clear />