Im not quite sure how this paginator works, as I've never used it. But I think the easiest way to fix this is to make sure that your Collection doesnt remove old models. I assume that when your data is being returned it is doing a set
on the collection. If you look at the backbone docs you can see that you can disable this method from removing models http://backbonejs.org/#Collection-set
If you'd like to customize the behavior, you can disable it with options: {add: false}, {remove: false}, or {merge: false}.
So when you are updating the collection, instead of just calling
myCollection.set([o1,o2,o3]);
you should be doing
myCollection.set([o1,o2,o3], {remove:false});