The XAML escape sequence and the navigation framework for Silverlight 4 and Silverlight 5 is discussed in a quick and useful tutorial by Alex van Beek.  He discusses a common scenario when using the navigation framework:

When you use the navigation framework in Silverlight, you probably also want to use an UriMapper, to shield your users from the complete path of the XAML files and the .xaml extension. Such an UriMapper could look something like this:

<uriMapper:UriMapper>

<uriMapper:UriMapping Uri="Home" MappedUri="/Views/Home.xaml"/>

<uriMapper:UriMapping Uri="About" MappedUri="/Views/About.xaml"/>

</uriMapper:UriMapper>

A small bug in the navigation framework activates the browser’s back button when the user navigates to your Silverlight application for the very first time. This isn’t that bad, except for the exception when the user actually presses the back button.  -- Alex van Beek

van Beek then goes on to show how he changes the UriMapper.  Go see if the tutorial gives you some useful insights.

Source: http://blogs.infosupport.com/silverlight-navigation-framework-tip-using-the-xaml-escape-sequence/