Is the "No Data API"part really true ?
I became curious as to how fmgateway connects to FMS, and so I followed the link above.
From some of the requirement steps, it looks as though it uses the Data API. This is not in any way to say that you haven't made a great find -- on the contrary, it seems like an excellent fit for you. I'm just trying to clarify (for myself) the technology that is underneath this that makes it work.