如何在Web应用程序中使用TWAIN驱动程序的自定义功能？

DWObject.SelectSource();
DWObject.OpenSource();
DWObject.Capability = 0x8001;
            DWObject.CapType = 5; //TWON_ONEVALUE
            DWObject.CapValue = 1;
            if (DWObject.CapSet())
                alert("successful");
            else
                alert("Source doesn't support this capatiblity");