Poptech when you can obatin the actual contractual agreement(s) between NeoMedia and their respective patent infringement attorney's, then you will be able to tell all of us exactly what the answer is to your question. Until then, nobody knows for sure what portion is fee based (cash outlay) and what portion is contingency. Albeit I would be very much inclined to believe the larger would be the later.
Regarding a defendant being represented by a contingency attorney...I simply don't think there are many such cases that work this way. However, you will need to contact your legal counsel to ask this question...as being a patent guru and owner of a firm specializing in them, I'm sure you have a few lawyers on retainer, no?