Dynamic Video Streaming doesnt work in iPad

Question

I am trying to create video dynamic streaming for iDevices,i tried this simple code under RTMP protocol and recorded video. it works in Flash Builder 4.6 simulator but in iPad it does not work:

<s:VideoDisplay 
        width="500" height="300">
        <s:source>
            <s:DynamicStreamingVideoSource 
                host="rtmp://serverID/vod/">
                <s:DynamicStreamingVideoItem 
                    streamName="MP4:sample1_150.f4v"
                    bitrate="150" />
                <s:DynamicStreamingVideoItem 
                    streamName="MP4:sample2_500.f4v"
                    bitrate="500" />
                <s:DynamicStreamingVideoItem 
                    streamName="sample3_1000.f4v"
                    bitrate="1000" />
            </s:DynamicStreamingVideoSource>
        </s:source>
    </s:VideoDisplay >

also i simplify that code as below:

<s:VideoDisplay source="rtmp://localhost/vod/MP4:sample1_500kbps.f4v"/>

and the result as the same,i mentioned that i used both FMS 4 and 4.5,How can i fix it? thanks