Sprite images

New to Datatables (having dropped SlickGrid in my development) but cannot see the answer to this question in the forum or anywhere.

For speed I wish to use a single sprite image for the sort and pager icons. I've constructed this and changed the styles used to reference it, for example

.sorting_desc {
    width:19px;
    height:19px;
    background: url('../images/SPSprite.png') 19px -38px;
}

but it is showing the other images apart from the desired one. HTML is not my strong point so I may be missing something obvious, or it may be the way Datatables uses the styles.

Thanks

Paul