Set visibility of RadCommandToolbar button conditionally for client-side bounded grid as per filter expression.

[Smruti Ranjan]

I have two requirements like :-

I) I have a RadGrid and it is having a RadToorBar as its CommantTemplate which contains a particular command button.
The grid is being populated on client-side through WCF service. Now i need this command toolbar button to be visible or hidden as per the filterexpression. If no filter expression for the grid is set then make the command tool bar button to be hidden.

II) For the client-side bounded RadGrid the header style does not change for the sorted columns as it works for the server-side bounded grids.

Please help me out in these two scenarios.
How to achieve these requirements for the client-side bounded RadGrid.

Thanks in advance.