c# - Simulating mouse wheel without move the mouse

Question

I'm trying to simulate the mouse wheel up/down using the PostMessage()

PostMessage(Handle, Msg, wParam, lParam);
PostMessage(Handle, 0x20A, 0xFF880000, lpara);

These values I got using Spy++, the lparam is created using the X Y coordinate.

So, here is my problem... When I try to simulate it in a window that I can scroll up/down, it only works if I move the mouse in the position of the scroll, the window doesn't need to be at the top/in focus, but the mouse must be at that position.

But the problem is that I need to simulate it without move the cursor itself, maybe with a "fake" movement or whatever.

Someone knows how to do that without move the mouse?