If G/L integration has been activated for the depreciation book which you want to post to, you can use a purchase invoice or an FA G/L journal.
Posting maintenance costs in an FA G/L journal is similar to posting in an FA journal. However, note that you must enter a balancing account in the FA G/L journal.
Open the 
Purchase
Invoice window.
Create an invoice and fill in the fields. For Help about a specific field, click the field and press F1. Note that the FA Posting Type field is not included in the standard layout, but you can insert it with the Show Column function. The Maintenance Code field is not included in the standard layout either, but you can insert it with the design facilities.
Click Posting, Post to post the invoice.
Filling In and Posting FA G/L Journals
Setting Up Maintenance Information
Posting Maintenance Costs from FA Journals
Viewing Maintenance Ledger Entries
Printing Maintenance Ledger Entries