Well, if they don't understand data structures and algorithmic complexity, they aren't going to be much good at serious Java programming, so I don't see that the language is an issue here.
They won't understand pointers, but good C++ programming typically doesn't use pointers in complicated ways. (There are exceptions, but since I don't know what your company does I can't tell whether they'd apply.) After all, you probably don't want your developers writing their own linked lists rather than using std::list.
They won't understand manual memory management, but that's a lot easier in C++ than it used to be. In modern C++, doing your own memory management has become harder, due to the potential of exceptions, so you want to practice RAII with pretty much everything (using auto_ptr, boost::shared_ptr, whatever).
If I were running things, I'd hire them if they looked good. I'd be aware that there might be problems (C++ is a more demanding language than Java, after all), and have some sort of idea how to deal with them.
There's no reason to avoid hiring people out of college just because they don't have the exact skills you want. The smart ones will learn, and you probably don't want to hire the ones who aren't smart.
