Yes, you will be able to bind a Fixed Virtual Account into an invoice. The benefit is your customer can use the same VA for multiple payment.
Use case for Fixed Virtual Account binded with Invoice is usually for recurring payment [subscription] 

Steps:

1. Create Virtual Account with specific parameter included virtual_account_number
   Parameter required

    "external_id":
      "bank_code": 
      "name": 
      "virtual_account_number": 
      "is_closed": true
      "expected_amount":

2. After step 1 got success response, copy the parameter "id" from body response 
3. Go to invoice creation and paste the parameter id from success response VA creation in the callback_virtual_account_id
4. Find out on how to create Fixed Virtual Account here and how to create invoice here

Step 1

Step 2

Step 3

Important Notes:
To create FVA binded with invoice for multiple payment with subscription model, you need to:
1. set parameter is_single_used: false
2. create invoice whenever end-user want to pay again into the previous VA number [create invoice every payment cycle]
3. If you need further assistance to understand better this feature, can contact our helpdesk help@xendit.co