VSTO/ClickOnce/Mage.exe resign app using EV Cert on a usb stick

I have developed a VSTO app for MS word. I need to make a change to the *.dll.manifest file. All of the example on the internet show that you have to use mage.exe to do so. However none of the examples tell you how to use mage when your EV Cert is stored on a usb stick. I would appreciate any help.