(Note: Section should be replaced with whatever section the autoscroll is in, and Speed should be replaced with the autoscroll speed. The Table of Values shows you which number makes which boundary move - 0 and 1 for a vertical scroll, and 2 and 3 for a horizontal scroll.)
Table of Values (from the LunaDLL tutorial)
0 = Top border
1 = Bottom border
2 = Left border
3 = Right border
Step 1: make sure you actually have LunaDLL
Step 2: make a lunadll.txt in your level folder and put
#Section
PushScreenBoundary,Section,First Boundary,0,0,0,Speed
PushScreenBoundary,Section,Second Boundary,0,0,0,Speed
TriggerSMBXEvent,0,0,0,0,1,Scroll
#END
Step 3: Make a SMBX event "Scroll", that sets the screen boundary to one screen - like you would with the regular autoscroll - and then move them back to where they once were in your whole level
Step 4: The "TriggerSMBXEvent" triggers the position event, and the "PushScreenBoundary" autoscrolls the screen! Tada!
Here's a level download for an example level:
https://www.mediafire.com/?i1o8k0uo8ti1uwo