Open 'Manage Accounts' control panel applet

I would like to open the control panel applet that shows the
currently existing users on a Windows Vista computer, showing
UAC prompt if necessary.
However, the following code only shows the page for the
current user:

ShellExecute(Handle, "open", "c:\\windows\\system32\\control.exe", "/name Microsoft.UserAccounts", NULL, SW_SHOW);

I also tried

ShellExecute(Handle, "open", "c:\\windows\\system32\\control.exe", "userpasswords2", NULL, SW_SHOW);

but this shows a dialog totally different from the one I get manually by
control panel -> user accounts and family safety -> manage another account -> UAC prompt

thanks in advance,