If you are writing Event Service clients, you can use the omniEventsCl.lib library instead of compiling the Event Service IDL files yourself. BUT I DON'T RECOMMEND IT. There is no debug version of the omniEventsCl.lib library, so developing with it would be awkward. For serious work, you will be far better off compiling the IDL files yourself.
If you do use the omniEventsCl.lib library, then make sure that you use the “multithreadded DLL” runtime with exceptions (options: -GX -MD), otherwise it won't work.