To post a purchase ledger invoice to a Vehicle record go to Batch Input of Documents on the main PL menu
Click on Yes at the Do you require VSB Postings
Enter the document details and then click on Transactions
Enter the vehicle details and click Accept
Click on the ellipsis at the right of the Options for Vehicle box and the spec lines that have a source of P will be displayed
Select the correct option and save the record.
If there are lines on the invoice that are not to be posted to VSB remove the Vehicle posting tick and the NL account can be entered.