I've downloaded Carbide.ui Symbian Theme Edition 4.0. But, i can't find the screen resolution(240 X 320) for it.
If you haven't already done it, upgrade Carbide.ui 4.0 to 4.1 as describe here. Then load the S60 3d Edition FP2 plug-in into Carbide.ui as written here. This will provide you with the desired screen resolution.