Well I finally figured this one out and what I was doing wrong all along!
Here is the pinout for connecting a SCART RGB input to a 1084:
I searched for this online a million times but I never found the exact thing I wanted. I was told what to do, but I still wasn't figuring it out, and no pinout was available. So enjoy that one.
My problem was the Composite Sync cable, normally when you build a cable, you connect to pin 20, that's fine when you are outputting, but for the input, you need pin 19. What a stupid error
You can either wire directly to a female SCART lead, but I didn't find any so what I did is I used any male SCART lead I had and bought a gender changer like this:
http://www.ebay.co.uk/itm/292290417615
Tested with my SNES, and it looked beautiful.
No excuse now not to connect all your RGB thingies to your 1084!