I checked the changelog and it seems that 1.2A(2) introduced the -comp command.
I think 1.1n didn't introduce a code wipe (since before -comp got introduced, I had to be very wary of changes in the savecode), so you might be able to convert your 1.1m(3) code directly into 1.2A(2).
If I remember right, 1.2A(9) introduced another code wipe (that then stayed the same until A(13)). So I'd try to -comp your code again in 1.2A(13) before comping into the current version.
So here's what I would try:
- comp your code into 1.2A(2) and save
- comp this new code into 1.2A(13) and save
- comp this new code into 1.2B(4)fix and save
Remember that you can't save in singleplayer. I recommend creating a 1 player LAN game to convert your codes.
If you have trouble finding older versions, check out epicwar or MakeMeHost. I guess they have those. Good luck!