Java :: Use Image As Video Stream While Recording On Media Server?

I'm creating application where user can record voice message, problem is that recorded file is passed to other encoding servers, that requires both video and audio streams to be present.

how can I use static image to emulate webcam and attach it to NetStream?

ns = new NetStream(nc);
ns.addEventListener(NetStatusEvent.NET_STATUS, watchRecording);
//ns.attachCamera(cam);
ns.attachAudio(mic);
ns.publish(fileName.text, "record");

[+]

Although I don't have access to application on WOWZA server I can negotiate with some one to add few lines and recompile it. So server-side solution in java is also an option here.