The Code

private void registerFluidBlock(BlockFluidClassic block, String identifier){
        Item item = Item.getItemFromBlock(block);
        final ModelResourceLocation mrl = new ModelResourceLocation(BigCapacitorsMod.modid + ":" + fluidStateModel, identifier);
        ModelBakery.registerItemVariants(item);
        ModelLoader.setCustomMeshDefinition(item, new ItemMeshDefinition()
        {
            public ModelResourceLocation getModelLocation(ItemStack stack)
            {
                return mrl;
            }
        });
        ModelLoader.setCustomStateMapper(block, new StateMapperBase()
        {
            protected ModelResourceLocation getModelResourceLocation(IBlockState state)
            {
                return mrl;
            }
        });
    }