Dll Injection

I need you to develop c++ classes for injecting a dll into another process. The dll will be injected from memory so your class will be supplied with the memory address and size of the dll. After loading a dll its headers should also be destroyed. It should also be possible to inject into a windows service and not just normal processes. The classes must work on xp, vista and windows 7. I have attached a library which accomplishes all this, but it doesn't work on windows service