jQuery zLayers and ipad/tablet touch commands

I am creating a web app which includes some scenes built with the beta/prototype version of jQuery zLayers, a free plugin that can be seen here http://www.devinrolsen.com/jquery-zlayers-parallax-plugin/

I would like my web app to work on touch screen devices as well as desktop computers.

The beta version of the plugin includes touch/swipe commands that work on iPad - ie, you can swipe your fingers over a zLayers 'scene' and the parallax effect works quite well. However, I would like to try and get the parallax to work *on a single touch* rather than your finger having to smear across the screen.

Does anyone have any idea how I could do this? I have made some modifications to the plugin and combined with the jQuery 'easing' commands to make the parallax 'drift' to your current mouse position - so this code is slightly different from that on the author's website -

/**
* jQuery.zLayer.full v0.3-BETA plugin
* Copyright (c) 2010 Devin R. Olsen
* Date: 01/09/2011
*
* Project Home:
* http://www.devinrolsen.com/jquery-zlayers-plugin/
*/
$.fn.extend({  
      zlayer: function(options){
            var defaults = {  
                   canvas: document,
                   confine:'',
                   force:'push',
                   mass:20,
                   ease:{
                         rate:500,
                         method:'easeOut'
                   },
                   rest:{
                         rate:500,
                         method:null
                   }
            },
            option =  $.extend(defaults, options),
            o = option,
            obj = $(this),            
            r = true;
            
            return this.each(function() {
                  $(o.canvas).bind({
                        mousemove: function(e){
                              if(r === true){
                                  obj.stop().animate({
                                          top:cal(e.pageY - obj.offset().top - obj.height() / 2,'y'),
                                          left:cal(e.pageX - obj.offset().left - obj.width() / 2,'x')                              
                                    },{
                                          queue:false,
                                          duration:o.ease.rate,
                                          easing:o.ease.method
                                    },0);
                              }
                        },
                        mouseleave:function(){
                              if(o.rest.method || r !== false){
                                    r = false;
                                    obj.stop().animate({
                                          top:0,
                                          left:0
                                    },{
                                          duration:o.rest.rate,
                                          easing:o.rest.method,
                                          complete:function(){
                                                r = true;
                                          }
                                    },0);
                              }                  
                        },
                        touchmove: function(e){
                            var touch = e.originalEvent.touches[0] || e.originalEvent.changedTouches[0];
                              x = touch.pageX - $(this).offset().left,
                              y = touch.pageY - $(this).offset().top;
                              if(x > 0 && y > 0 && (x < $(this).width()) && (y < $(this).height())){
                                    obj.css({
                                          left:cal(x - $(this).width() / 2,'x'),
                                          top:cal(y - $(this).height() / 2,'y')
                                    });
                                    r = false;
                              }                  
                              e.preventDefault();
                        }
                
                  });
            });




            function cal(v,a){
            v = (o.confine === a)? 0 : (o.force === 'pull')?
                  v / o.mass :  -v / o.mass ;
            return v+'px';            
            }
      }
});

Many thanks in advance for any input or ideas.

Andy