What I did is this (if I got this part correct - "then multiply the other view border dimension"):
camera->left = -cam_boarder * (screen_size.x / screen_size.y);
camera->right = cam_boarder * (screen_size.x / screen_size.y);
camera->bottom = -cam_boarder * (screen_size.x / screen_size.y);
camera->top = cam_boarder * (screen_size.x / screen_size.y);
But it doesn't fix my problem, here are the results:
1024x768
1280x800:
Greets!