Interfacing deliveries with third party system in a wms enabled organization

 I am trying to deal with the fact that wsh api's do not work in a wms enabled organization

my thoughts was perhaps doing a work around where I would split an order line when the line is underpicked and then process the line with a pick confirm to stage it--I am having trouble splitting the line--has anyone a suggestion as to what I may look at?  I can split the line in the form