Hi Arkar,
To be able to select the different bitrates manually in JW player, you need to provide width & height information in the smil file. Jw player uses this to build the menu and determine the bitrate to start with based on the player size. The smil file examples on the page you linked to do not show this which is an oversight on our part however the directions for creating a smil file in the Manager do show the steps for adding width & height information.
To do RTMP ABR playback in JW Player, you do need a meta tag.
Wowza has a specific url that you can use in the player that will dynamically create the correct smil file for jw player with the correct meta tag included. It does so by reading your original smil file and returning a JW Player specific file. There are a few other minor differences between the smil file used for HTTP streaming and that used by JW player which is automatically handled.
In your player code, use the following for the file setting.
http://<wowza-ip>:1935/vod/smil:bigbuckbunny.smil/[B]jwplayer.smil[/B]
Roger.