i need NHibernate.ByteCode.Castle source code

I need to get into FluentNhibernate and NHibernate code so i rebuild the solutions and used the new assemblies, but the problem is that there is an assembly called NHibernate.开发者_JS百科ByteCode.Castle.Dll which refuses to load the my own version of Nhibernate and keep telling me that the Public Token doesn't match, so where can i get the source code for this assembly, so i can reference my NHibernate assembly and rebuild it???

or may be the question is : is it open source ???

:$ how stupid I am !!!!

it comes with Nhibernate source code,but what made me confused is when I opened the Nhibernate Solution, the Nhibernate.ByteCode.Castle project wasn't there! !!!

but there is another solution file called NHibernate.Everything.sln, i opened it, and voila !!! there it is in the solution.