Hiding navigation pane in mscrm2011:

Javascript approach:

//Ensure navitem is "quoted" to represent string
// bool: true = Visible, false = removed
var objNavItem = Xrm.Page.ui.navigation.items.get(navitem);
objNavItem.setVisible(bool);

C# code approach:

/// Retrieve the sitemap

QueryExpression query = new QueryExpression();
query.EntityName = "sitemap";
query.ColumnSet = new Microsoft.Xrm.Sdk.Query.ColumnSet(true);

EntityCollection col = _service.RetrieveMultiple(query);

Entity sitemap = null;
if (col != null && col.Entities.Count > 0)
   sitemap  = col.Entities[0];
 ///Parse the sitemap entity to an XDocument object
 string sitemapcontent = sitemap["sitemapxml"].ToString();
XDocument sitemapxml = XDocument.Parse(sitemapcontent);


You can now change the sitemap by modifying the sitemapxml object. After you made your changes, it's time to save these changes.

//// Update the sitemap
sitemap["sitemapxml"] = sitemapxml.ToString();
_service.Update(sitemap);


//// Publish the sitemap

PublishXmlRequest request = new PublishXmlRequest();
request.ParameterXml = "<importexportxml><sitemaps><sitemap></sitemap></sitemaps></importexportxml>";
_service.Execute(request);