plupload removeFiles

I'm trying to remove files with not allowed extensions on the FilesAdded event. (I can't use the filter parameter as I need an exclusive list).

I have some code a bit like this:

uploader.bind('FilesAdded', function(up, files) {

    var count = files.length;

    var i = 0;

    for (i;i<count;i++) {

        var validExt = validate(files[i].name);

        if(!validExt){

I need to remove the files added if the extensions aren't valid. I've tried the following:

uploader.splice(i,1)

uploader.removeFile(files[i]);

uploader.refresh();

The FilesRemoved event is fired, but removed files still get uploaded with uploader.start().

I don't know if this is a bug in the program, or too obscure to expect an easy answer to, but if anyone can help, I'd be really grateful. I don't think I'm missing anything obvious.

Thanks.