There isnt anything on the market compatible with the inbuilt Panasonic trigger I am afraid, Panasonic suggest the DMW-FL360L flash, however since you already have a flash I suggest you use Hahnel remote and trigger here. Thought your camera isnt listed as compatible it should be, and if you go to one of the Jessops stores you can certainly try before you buy.
Hi Brian,My name is ***** ***** I will try and help with your question. I have had a look and done a bit of research and as mentioned before there is no wireless adapters listed as being compatible with your camera but I had the same issue when i looked for my camera.
I personally use a low cost receiver and transmitter like this one here. http://http://www.ebay.co.uk/itm/16ch-Wireless-Remote-FM-Radio-flash-Speedlite-Trigger-w-2-5mm-PC-2-receiver-/310802569598 it works well with my cannon and my studio flash timing is sometimes an issue and takes a bit of getting used to on setting the camera.I would suggest having a look at the cactus wireless flash http://www.cactus-image.com/v6.html.I am sorry that i cannot give a definite answer to your question but with nothing being listed as directly compatible it makes it difficult.I hope my advice helps a little if you need anymore advice please feel free to ask.