Having a spot of bother in setting up for windows usage.

I'm attempting to have a windows box syncing to a server (over ssh) and a linux box also syncing against that*

So, on each machine I do

git init git annex init

On the windows and linux desktops I then do a

git remote add server serverdetails.

Now the problem is that if I don't add files to the repos on the machines, they won't sync as there is no branch checked out; and if I do then the first one is fine but the second will fail as it doesn't allow fast-forwards. What am I doing wrong? I've tried making the server repo bare / not bare.

I'm using the latest nightly windows build, and a build from git from today (29d5bb94b4512cfe3072c9ff840cb0ce9f2af744)

*Actually I'm trying to do something a little more complex than that, but this is the simplest version I can come up with.