64-bit Toolkit remote access to 32-bit C-Gate

I've been trying to find a reason why my Win7 (64-bit) PC can't talk to my 32-bit C-gate Linux install but after lots of playing around today I don't seem to be able to get Toolkit on 64-bit Win7 to talk to C-Gate on 32-bit Windows or Linux, where it works fine 32-bit Toolkit to 64-bit C-Gate. (32-bit to 32-bit and 64-bit to 64-bit is fine.)

Is this a known issue, or have I got something wrong?

All running TK 1.12.5. If access.txt isn't set up correctly C-gate logs a rejected connection but otherwise it looks fine but just doesn't work (this is all a level 9 logs shows):

Code:

20130904-133940 803 cmd27 - Host:192.168.251.30/192.168.251.30 opened command interface from port: 49890
20130904-133940 899 sys Debug: New Command Context: cc014 = AccessContext Session 192.168.251.30/192.168.251.30#28
20130904-133940 766 cmd27 - Response: 201 Service ready: Clipsal C-Gate Version: v2.9.5 (build 2460) #cmd-syntax=1.0
20130904-133940 804 cmd27 - Host:192.168.251.30/192.168.251.30 closed command interface from port: 49890

As an aside, I have a site where I remotely access C-Gate via SSH using tunnelling so that the remote C-Gate appears as if running on localhost. This seems to work fine even though it means my 64-bit TK is talking over SSH to a 32-bit C-Gate (on Linux), albeit that it thinks it's talking to a local C-Gate. When I went to site I then tried using my 64-bit TK to talk remotely to the 32-bit C-Gate and it didn't work, and that was what sent me looking for the cause. So the same TK that will talk to the same C-Gate when it thinks it's local won't talk to it when configured as remote.

As a further aside, I have a 64-bit Linux desktop with TK installed under Wine and it is able to talk to the remote 32-bit C-Gate, albeit that it then crashes when I try to open a project.