How to debug the Exch2010Extension.dll

If you find yourself having to debug the Exch2010Extension.dll in the FIM Sync 'Extensions' folder, then you want to attach to the MMSSCRPT.exe process, and not MIIServer.exe.

2015-04-30 07:21:52,196 --1-- DEBUG [Exch2010Extension.Exch2010ExtensionClass] 
Process information
-------------------
ID          3704
Name        mmsscrpt
ToString()  System.Diagnostics.Process (mmsscrpt)
CPU time
 Total      00:00:02.4843750
 User       00:00:02.0156250
 Privileged 00:00:00.4687500
Memory usage
 Current    54,919,168 B
 Peak       54,919,168 B
Active threads      21