Hi,

you have two ways and both of them works:

First  (with creating and adding products) :

1. create service product and set up dedicated accounts directly from product template "Accounting" tab or from product category (for more generic use):

2. create vendor bill and add previous created product as a bill line:

3. the journal items will be:

Second  (without creating or adding products) :

1. add Label into bill line like this:

2. the journal item will be:

Note: the tax line from previous bill comes from product template.

3. if this bills is recurrent, then next month you can choose it using Auto-Complete feature:

Note: it will automatically fills bill line based on old bill.

hope it will help.