Recognized deferred revenue when service is delivered

Customer does not have the Deferred Revenue module.

Does anyone know of a way to accomplish the following scenario:

1. Invoice customer for sold item and install is also invoice up front.
2. The install credits a deferred revenue account rather than revenue
3. When the install is complete, via a Field Service invoice, we need to debit the deferred revenue account and credit revenue- therefore recognizing the revenue when the service is comlete.

Thank you for any input you can provide.