In V8.82 you can now allocate serialised items in Sales Orders, AR Reserve Invoices and Stock Transfer Requests (these are a new document and act as a precursor to Stock Transfers but with no stock or GL changes)
To access the Serial Number Allocation screen click: CTRL + TAB whilst in the Qty Column (or right-click on row and choose Batch/Serial Number) The serial number can then be allocated to the specific document from this screen. Once allocated, this information will be cascaded through to any subsequent documents in the chain e.g. from sales order to delivery to invoice.
Once a serial number has been allocated you cannot allocate it to a different document.
Should you wish to 'De-allocate' a serial number from a document, click CTRL + TAB whilst in the Qty column (or right-click and choose Batch/Serial Number) and de-allocate from this screen.
You can see which serial numbers have already been allocated and to which documents via the Serial Number Transactions report (the status will show as 'Allocated' and if you then highlight the item, the document it has been allocated to will be shown in the transaction detail for the row).