BGP doesn't appear to support eBGP

I tried configuring a BGP neighbor using eBGP rather than iBGP (i.e. I put the controller in a different AS to the neighbor and configured the AS of the controller on the neighbor).

BGP fails to come up as the controller rejects the neighbor's BGP open for not matching exactly what it expects.

What we need is a way to configure the remote-as on a per-neighbor basis so we can enable eBGP.