How To Fight International OSS License Violations?

sirshannon asks: "Frans Bouma's LLBLGen is a free, open source code generator that he licensed under the BSD license so that anyone could use it in any way, as long as they gave him some credit. Now Codease has released a product that apparently uses his code for 90% of the functionality but doesn't bother to attribute it to him. Frans lives in The Netherlands, Codease is in Singapore. What is the correct way to pursue this?"