sitemapnode - url contains a space in the querystring, no breadcrumb when navigating to it

One of my sitemapnode elements contains a url with a space in the querystring (Visual Basic).
When I navigate to the page, the URL is .... Visual%20Basic and therefore cannot be found in the siteMap so the breadcrumb is no longer visible.  How can I get around this?

<siteMapNode url="~/Categories/Titles.aspx?Language=Visual Basic" title="VB" description="VB" />

I have found sites that talk about overriding FindSiteMapNode.  However, I have not found an article with sufficient detail ... a tutorial and/or a working code sample would be great.