Link sales order to contract after creation

Hi SAP Gurus ,

Objectives or problem statements:

1. Is it possible to create a sales order (without reference to a contract). And after creation, link it to a value contract without customization?
2. Is it possible to add line items to an order created with reference to a value contract and make sure that the new line item is also linked to the contract ?

Context

• We are trying to implement sales order creation with respect to contracts for make-to-order scenario.
• Business stakeholders currently upload sales orders (without reference to contract) using a mass upload tool from excel (using Winshuttle )
• If we move to order creation with reference to contract then it might become challenging to perform order uploads using Winshuttle --- which means more data entry work

Preference

1. My first objective is the best case scenario where we would be able to create sales orders like we do now(without reference to contract) and then simply link it to contract after with another Winshuttle script.

2. If I cannot achieve objective 1 then I would like creating a sales order with reference to the contract and then add line items to the sales order after with Winshuttle. This option is only valid if the line items I add later will also be linked to the contract reference in the sales document header --(VBAK-VGBEL). The challenge i have found in doing this in our quality system is that the new items do not show the conract as preceding document in VBFA-VBELN field

Thanks for taking the time to try and help me out !

Cheers !

Akash