A quick look at the Aus manual does show that you should have an option on the left hand side of the screen (in s-mig or manual-mig mode) to switch between torch or spool gun.
This is on a machine with euro connector.
It looks like this is showing all the time (regardless of having a spell gun connected) so more than likely at least a software solution is required.
If yours is triggering the mig (presuming there are NOT 2 little pins inside the euro connector on the spool gun?) It would suggest at least some of the wiring on the 8pin is in place.
Get the wiring diagrams and see what's what.
Or, as earlier, plug the tig torch in and see if that will trigger the wire feed motor in mig mode. That will at least give you more of an idea on how it works.
thanks Hotponyshoes, you can now see why I thought that it would just work, the machines look identical, and the spool gun said made for the rebel emp215ic, so I am sure it is just a software thing
Going back to the original , we have a 13ft 'Tinnie' built by a division of Crysler . All solid rivited, bit much thinner than the OPs at around 1mm. It does seep at the seams a bit, but, at over 60yrs old, no surprise. I do a bit..
Frankly, I would source some solid rivits and redo it as original. Mind you, I have quite a lot of experience on riviting aircraft together.
Tip: get a cheap air chisel and mod one of the bits to have a hollow end for the rounded heads. Worked for me on a serious rebuild on a Twin Piper.
I don't understand why anyone in this day and age would make hardware that can't be simply flashed with a USB file etc.
Upgrades like spool guns etc - in this case it would have worked well, if the firmware had been designed properly?