Set the 'confirmType' option to my_function:
$('#l28').Aplus({confirmType: function(msg,callback){
var div=$('<div id="my_confirm">');
div.appendTo('body').html(msg+'<br/><input type="button" value="OK"> <input type="button" value="Cancel">');
div.find('input:button').click(function(){
if(this.value=='OK') callback.apply();
div.remove();
});
}});