Screen scrolling with the mouse wheel?

I'm working on a dungeon crawl in MMF2 that is mouse-driven and so far has been coming together very nicely, however at this time I am having to use 'always centre screen on' an invisible object controlled by the keyboard to scroll the screen up and down. It's effectively an invisible active element that is locked on the up and down option of 8 direction movement.

What I want to do is eliminate the keyboard entirely and have that active object move when I use the mouse wheel instead. Can anybody give me an idiot's guide in how to do this? It's the one glaring flaw in a demo build that I'm becoming increasingly proud of and would like to take further.

Thank you so much - this has been a very big help. It's solved the last big change I wanted to make before prepping a demo for release