Space shooter scrolling

How do I do R-Type/Gradius/etc. style scrolling in Construct? You know the type of scrolling where the screen is always moving forward (while the player moves independently) regardless of where you are on screen? I can't seem to figure it out.

Since I'm making one of these, I can help you out.

I'm doing it two ways, depending on the level:

1: No actual scrolling - the background moves instead.

2: Create a 'camera' object - I use a box - with a movement and center the screen on that. Move the box, and always move the ship the same amount as the box moves. I'm using private variables to store the X and Y position of the camera from the previous frame, and moving the ship the difference between the frames. Both RTS and bullet movement work great for scrolling.