Does AMS standard support dynamic RTMP streaming with JW-player and .smil files?

AMS standard or otherwise supports both RTMP and HTTP streaming.

Whether a player(JW player in your case) can play those streams is upto the JW player functionality.

If you are behind firewall that means(I guess) only 80 port if open for you...In that case you have the following options:

1) RTMP Streaming---which goes over 1935 port obviosuly will not work. You can instead configure(very easy to do) your server to stream via rtmpt(i.e rtmp tunneling over http) or rtmpte(encrypted rtmp tunneled over http) or rtmps(if you firewall opens 443 port for you).rtmpe, rtmpet and rtmps and just variants of rtmp. Please see adobe documentation for details.

2) HTTP streaming -- HTTP server by default listens on 80 so this should work for you...However note that there is more lag/delay playing live stream in HTTP streaming than in case of RTMP streaming. if you are playing VOD/static content then HTTP streaming should serve you just fine.