in ax by default you can use this function by enabling product registration process,
where you receive 10 qty from 50 ordered qty then you have to make registration of 10 qty and while making product receipt you have to selected registered items and then enter the number of product receipt and enter OK.
this will received only 10 qty only and rest 40 qty will be show ordered.
you can contact me on skype fopr further detail for the same.
in item model group select registration require just tick mark this one then while receiving items you have to register the items before it is received.
the register process can be done by two ways one from item arrival journal and second from opening the Purchase order click receive tab and here click product receipt and register all items one by one by clicking update line.
select the line and click update on right hand side one window will open.
click for the auto check box above area where item is listed with status order once you click auto that line will come down here select the location and warehouse and post all.
so this is the registration process now in case you have received 10 pcs from 50 pcs then manually change quantity from 50 to 10 in below area in same window and post all.
then enter the product receipt number and post, to verify you can click total button which will give you the total value of the received stock.
contact me on skype will show you the live scenario via team viewer.