Awhile back I wrote about an resxtop bug found in vMA 4.1 in which it no longer functions with vMA's vi-fastpass component and still requires you to provide the username and password even though vi-fastpass has been initialized for a given target. There was also a slight quirk when using esxcli and vi-fastpass, in which you had to specify in addition the --server of your ESX(i) host which allowed you to utilize vi-fastpass.
With the latest release of vMA 5, both of these issues have now been resolved for both ESXi 5 and ESX(i) 4.x. I would highly recommend you download the latest version if you would like to make use the vi-fastpass component in vMA.
Here is an example of using vi-fastpass with resxtop:
Here is an example of using vi-fastpass with esxcli: