Background: Wikipedia search 'Container deposit legislation'

Each product we sell has an attached Deposit product that must be automatically added whenever the product is sold. These attached Deposits must be tracked separately and are non-taxable.

Example:

Baileys Irish Creme 750 mL $22.99 (sell) - is taxable

Deposit 0.10 $0.10 (sell) - is non-taxable

The addition of these deposits to all sales, sales orders, etc. must be automatic. They must show on receipts/invoices as a legal requirement. (Adding them manually isn't an option due to our high sales volume and possibility for error)

I've played with BoM but it only seems to affect things on the purchasing side. Tried the Product Bundle community module but it didn't seem to affect our sales documents at all (e.g. when we added a base product to the sale like Baileys, it wouldn't automatically add the bundled product we specified).

Any ideas how I can accomplish this?