data-icon="arrow-l" not working on iphone while using jquery mobile alpha 3 version

I am designing an app for Iphone using PhoneGap and Jquery mobile framework.(alpha 3 version) I am adding this code for back button data-icon="arrow-l" to display an left sided arrow in the back button, its working fine in the simulator. But while running the same application on the device the arrow is not getting displayed.

Surprisingly the code, data-icon="plus" which I am using for an add button is working fine both on 开发者_StackOverflow中文版simulator and the iphone.

Any solutions??? Thanks in advance

There were some problems in the Jquery mobile framework files. I fixed this by simply updating the jQM framework files.