One thing that I would like to recommend is to really look at a "fresh" Windows 2008 R2 config and use that as a baseline, otherwise you will likely have some things missing or behaving differently. For example in administration.config in Win7/2008R2 we added a few UI modules that were not in 2008 so you will miss those features. In particular you should add:
<add name="ConfigurationEditor" type="Microsoft.Web.Management.Iis.ConfigurationEditor.ConfigEditorModuleProvider, Microsoft.Web.Management.Iis, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="RequestFiltering" type="Microsoft.Web.Management.Iis.RequestFiltering.RequestFilteringModuleProvider, Microsoft.Web.Management.Iis, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FastCgi" type="Microsoft.Web.Management.Iis.FastCgi.FastCgiModuleProvider, Microsoft.Web.Management.Iis, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="ASPNETAuthorization" type="Microsoft.Web.Management.AspNet.Authorization.AuthorizationModuleProvider, Microsoft.Web.Management.Aspnet, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="ASPNETErrorPages" type="Microsoft.Web.Management.AspNet.ErrorPages.ErrorPagesModuleProvider, Microsoft.Web.Management.Aspnet, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
And of course if you install WebDAV:
<add name="WebDAV" type="Microsoft.Web.Management.Iis.WebDAV.WebDAVModuleProvider, Microsoft.Web.Management.WebDAV, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
And of course the entire FTP assemblies that are new in Windows 7/R2.
<add name="FtpSites" type="Microsoft.Web.Management.Ftp.Sites.SitesModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpDirectoryBrowse" type="Microsoft.Web.Management.Ftp.DirectoryBrowse.DirectoryBrowseModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpMessages" type="Microsoft.Web.Management.Ftp.Messages.MessagesModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpUserIsolation" type="Microsoft.Web.Management.Ftp.UserIsolation.UserIsolationModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpSsl" type="Microsoft.Web.Management.Ftp.Ssl.SslModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpAuthorization" type="Microsoft.Web.Management.Ftp.Authorization.AuthorizationModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpIPRestrictions" type="Microsoft.Web.Management.Ftp.IPRestrictions.IPRestrictionsModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpLogging" type="Microsoft.Web.Management.Ftp.Logging.LoggingModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpFirewall" type="Microsoft.Web.Management.Ftp.Firewall.FirewallModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpAuthentication" type="Microsoft.Web.Management.Ftp.Authentication.AuthenticationModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpCurrentSessions" type="Microsoft.Web.Management.Ftp.CurrentSessions.CurrentSessionsModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="FtpRequestFiltering" type="Microsoft.Web.Management.Ftp.RequestFiltering.RequestFilteringModuleProvider, Microsoft.Web.Management.Ftp, Version=7.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
etc, this is only in administration.config, similarly in ApplicationHost.config we changed a couple of defaults like the delegation of Custom Errors and others.
Bottomline hand-crafting a 2008R2 config from a 2008 config is better done if following a template of what you are trying to match and try to retain some of the out-of-the box settings for compat with the new features (like WebDAV which is now available in the box).