We did add the HTTP API that in theory, should be the what AmiBroker is expecting, same as QT, in the beta version of MT: http://www.medvedtrader.com/beta
in the program you would enable the API on SETTINGS / APPLICATION /API
However, one of our users tried it with AB and said that it wasn't working. I am waiting on Tomasz to get back to us about that. Maybe you can give it a try and if it does not work, contact him too?