Are brackets the easiest way to attach trellis above a fence?

My passionfruit vine’s outgrown the steel fence and I want more privacy, so i’d like to attach a 2 foot trellis above the fence. That way the vine can grow higher and block the view above the fence.

Would the easiest way to do this be to attach some flat metal bars to the existing fence posts by using brackets, then attaching the trellis to the flat metal bars? I really don’t want to install new fence posts, or pay a professional.

Do you have any sketches, pictures or links to the brackets you have in mind?  An experienced fence modifier may think you mean one thing and tell you it will work, when you really mean something else and it won't.

Sorry I mean a lattice. I figured it’s probably a straightforward thing to do. I’m not sure if the hand-high bit of post above the bar is high enough to support a trellis

I'm sure that bit of exposed fence post pipe is strong enough to hold 2' more of fence or lattice or trellis.  I'm guessing you could use a smaller pipe and stick it down inside it, or a larger one that goes over it for a 2' vertical support.  Then attach the lattice to that new piece of pipe.  Or any number of other ways.  

Thanks for the ideas Mike! The other day I placed a stake inside the metal pipe and it was so deep I’d have trouble getting a long enough metal bar/pipe, and I don’t have a metal cutter. But putting a pipe slightly wider than the present pipe seems pretty easy: just sit it over, somehow make it fit snug to prevent creaking and movement, then attach a trellis. That seems the best option so far.

Depending on how long you want it to last, you could put a wooden stick down in the hole that is snug to the inside of the pipe and gets fatter so it won't slide all the way down.  Then attach the trellis to it.

If you have a smaller pipe that you could fit inside there, wrap it with electrical tape until it fits more snugly to avoid wiggling.  Then drill a hole through it and stick a pin or bolt through to act as an upper stop.  So as the small pipe slides down into the bigger pipe, the bolt/pin keeps it from dropping lower than you want.

Or with a bigger pipe for the extension, just wrap the existing pipe with tape until the diameter is closer to the big pipe to prevent wiggling and movement.

I'm sure there are 17 other ways to do this as well

Watch your local laws on fence height.
Hopefully you live where no one cares,  but I've been burnt by complaints from asshole neihbors.
Extending horizontally from the fence to a parallel line of trellis might be more work up front but less when harvesting.

Yeah as it’s not my front fence it’s probably on, and as a trellis is cheap to buy and install by myself it’s no financial gamble. I mai lay want it for privacy as people can still my head when walking past. I just want to add about 1 foot in height.