I can't use Sitemap when I use UrlMapping - asp.net

Question

when I create folder for every page and remap those in web.config , appeared this problem .
1)I can't see content of pages.
2)When I use navigation controls , my web.SiteMap don't work and don't show path of pages.
what is problem in my project , and what I solve that ?
this link is my web site :
Urlmapping code :
<urlMappings>
<add url ="~/HOME" mappedUrl ="~/Default.aspx"/>
<add url ="~/a" mappedUrl ="~/a.aspx" />
<add url ="~/a1" mappedUrl ="~/a1/a1.aspx"/>
<add url ="~/a2" mappedUrl ="~/a2/a2.aspx"/>
<add url ="~/b" mappedUrl ="~/b/b.aspx"/>
<add url ="~/b1" mappedUrl ="~/b1/b1.aspx"/>
<add url ="~/b2" mappedUrl ="~/b2/b2.aspx"/>
<add url ="~/b3" mappedUrl ="~/b3/b3.aspx"/>
<add url ="~/c" mappedUrl ="~/c/c.aspx"/>
<add url ="~/c1" mappedUrl ="~/c1/c1.aspx"/>
</urlMappings>
SiteMap code :
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
<siteMapNode url="~/HOME" title="Home" description="Home Page">
<siteMapNode url="~/a" title="page a" description="page a">
<siteMapNode url="~/a1" title="page a-1" description="page 1 of a" />
<siteMapNode url="~/a2" title="page a-2" description="page 2 of a"/>
</siteMapNode>
<siteMapNode url="~/b" title="page b" description="page b">
<siteMapNode url="~/b1" title="page b-1" description="page 1 of b" imageTitle="lake"/>
<siteMapNode url="~/b2" title="page b-2" description="page 2 of b" imageTitle="wolf"/>
<siteMapNode url="~/b3" title="page b-3" description="page 3 of b" imageTitle="thunder"/>
</siteMapNode>
<siteMapNode url="~/c" title="page c" description="page c">
<siteMapNode url="~/c1" title="page c-1" description="page 1 of c"/>
</siteMapNode>
</siteMapNode>

Answer 1

The problem is that the Url your are wanting is a actual folder in your wbesite so IIS picks this up first. There are acouple of ways to get around this.
Change all the .aspx filenames to be Default.aspx and these will be picked when you type http://website/a for example if you have a folder called "a" with Default.aspx in it, remove all the entries in the urlMappings
Have the URL as a different name to a actual directory
Use ASP.Net URL Routing that has been introduced in 3.5 SP1 look at Chis Cavanagh blog post on it.
Use as Jose mentioned the ReWritter

Answer 2

I can solve my problem .
you should create folder whit name Default and create page whit name default too and then use web.sitemap in navigation controls .