Those little bits of brown dirt are burn out...sorry for your loss :-)
The only "official" service available on a Z240 is complete replacement of the internals. Sea Optics has done one strobe for me themselves and sent one to Japan as well. While I appreciated that they could do it, in both cases this took a long time and many unanswered phone calls to them.
Steve's website is here: http://www.tfmengineering.com.au/Full disclosure, he is a friend and dive buddy as well as a business owner. He did a fair bit of experimenting with one of my Z240s to find the right replacement tubes, and has since changed over four sets. It's nice to have full output out of them again.
I use professional photographers insurance in Australia, which covers all kind of useful things like checked baggage on flights, stolen from vehicle, rentals while awaiting repair/replacement, etc. It also has a rider to cover water damage from leakage while in use in the housing. Taking the camera body out in the rain is not covered, on the other hand.
Might be worth investigating if similar providers exist for professional photographers in your part of the world?