Setting property Enable32BitAppOnWin64 for IIS 7 in C#

[Mushq]

ServerManager mgr = new ServerManager();
mgr.ApplicationPools["test"].Enable32BitAppOnWin64 = true;
mgr.CommitChanges();

Above code should set property Enable32BitAppOnWin64 to true for application pool having name test, but it doesn't do that, can anyone please tell what am I doing wrong.

Please note that ServerManager class is present in Microsoft.Web.Administration namespace.