Trouble with Genesis and C= 1070 Monitor

[Mask of Destiny]

I'm trying to get my Genesis to work with an Amiga 1070 monitor I have, but I'm having trouble getting a decent sync signal. Using the CSYNC pin on the A/V port gets me no picture, same thing using the /CSYNC in and out pins on the CXA1145. The only way I can get any picture at all is to use the composite video pin on the A/V connector as composite sync, but I can't get a stable sync on that.

Messing around a bit I accidentally shorted my sync wire against both pin 10 (/CSYNC IN) and pin 9 (Audio Out) and to my great surprise I got a perfectly stable picture.  Connecting the sync line to /CSYNC Out and disconnecting the ground line also gave a stable picture (but of course it looked like crap because the RGB levels were wrong).  So I'm guessing I need to use /CSYNC out with a little bit of extra circuitry to adjust it in such a way that my 1070 likes the signal.  I just don't know what exactly it is I need.