Hi, Mac. I agree with John2000 that just covering up the rot is not a good fix. And his way will certainly work well.
I had a small section of rot on an inside corner of mine and did not really want to tear out a lot of other molding to fix it so I used another method. Use a high speed rotary tool like a Dremel tool or one of their bits in your regular electric drill. Grind out any wood that seems punky. Mix up some automotive Bondo and stick it in the hole. Remember that you have a very short working time and you may have to apply several thicknesses until you get it up to the face of the fascia board. Sand it back down smooth, prime and repaint. Then you can wrap it with the aluminum if you wish.