Radio Button List arrow keys and Tab order Not working

I have radio Button List, Its Auto post Back property is True.

when i select one radio button go through arrows from one radio button to other .
It is possible But when give Auto post back true it is Not working

Give any suggestions I want go throgh arrow keys or Tab

When i Take Individual Radio buttons with same group Name,Auto post-back false Tab Order
working,
When Auto Postback True tab order Not working.

Thanks Srinivas.