What I did so far:
1. Decompiled both dll's into a single code file.
2. Compared those code files with WinMerge
3. Found the changed lines of code in the code files (line 249482 - doesn't help though because how am I supposed to find this exact line in about a thousand sub-directories?)
4. Tried working with .NET Reflector and the add-in called "Reflexil 2.0"
5. Get myself totally confused with the mass of information I am totally unfamiliar with.