Exchange 2010 to 2013

So today I tried to install Exchange 2013 and do coexistence with Exchange 2010,
1. Install SP3........ done!
2. Install RU6....... done!
3. Install Exchange 2013.... fail!?!?!?

Apparently Exchange 2013 thinks that the other Exchange Server is still 2010 SP1..
I tried to reinstall the SP3... but it's already on RU6, so I tried to reinstall the RU6, still won't do...
After googling around and messing around, I found out that the Exchange installer failed to update the AD configuration, the system configuration still showing 14.1.x which is SP1, damn now I found the problem.

2 days later, I still can't find the solution, registry says the correct version, technet shows nothing, apparently some people in internet face the same problem with no solution...
No choice but messing around with ADSI, first I found out that serialNumber and msExchVersion relates to the version Exchange Management Console version showing, changing the entry was easy, but it still won't solve the problem. So I tried to use all my Google jutsu... until I found 1 (yes, only 1) website which have more or less the same problem(he use 2007 instead of 2010). Apparently, serialNumber does nothing other than cosmetic purpose, Exchange use binary format for version detail which saved under the name of versionNumber, this website told the other guy how to fix it. When faced with 2010 SP3 error on Exchange 2013, all you need to do is make sure that you really have SP3, then do this

open ADSI, then expand CN=Configuration], CN=Services, CN= Microsoft Exchange, CN=[ExchangeDomain], CN=Administrative Groups, CN=Exchange Administrative Group (FYD...), CN=Servers, CN=[Your Exchange Server]
right click and shows properties, find the versionNumber then change the number into
1937998019 if you use Exchange 2010 SP3 RU6
1912832298 if you use Exchange 2007 SP3 RU10
you can also fix the version number for cosmetic purpose :D

After that you can go back to other server to install Exchange 2013 and start migrating!

Now I need to get back for ASE exam...

Credit: http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/Windows_Server_2012/Q_28144192.html
http://blogs.msdn.com/b/pcreehan/archive/2009/09/21/parsing-serverversion-when-an-int-is-really-5-ints.aspx