FdinById is a typo in DependencyManagerLinkage.h I will file a defect to correct to ElementHandle FindByID that is exported in DgnPlatform\ElementHandle.h+631 in the MicroStation CONNECT Edition Update 4 SDK. There is also a code snip of it being used in ..\Databases\odbcoledbdemo\odbcoledbdemp.cpp+291/411
HTH,
Bob