Using vb6 dll in C++

Hi all,
I have this ancient library written in Visual Basic 6 which I'd like to use in my C++ (.NET 2008) project. When I compile the vb code to a .dll it gives me a .lib as well. I can start a new C++ project and include the .lib, no problem. But say that I made a VB function like this:

Code:

---

public function bla()
    msgbox "Hi there!"
end function

---

I can't seem to be able to call this function from my C++ project like this:

Code:

---

void bla();

void main() {
    bla();
}

---

Normally it links these things automatically. However it doesn't seem to find the function in the library.

Is this even possible?

Thanks in advance!

The Vile Guy

EDIT: c++ .net version added and vb function made public