Quotes - manually add Part Number

Hi All

I have previously used SugarCRM and in the Quotes area, if we have not had a Product listed or were doing a one-off product it has been possible just to type in a Part Number in the Part number area of the quotes and it would be accepted - even though the part did not exist.

In SuiteCRM 7.2.1 this is not accepted is there a way that I can manipulate the code to accept this or is there a simple work around?