Individual invoice number prefix per multi-store

I'm evaluating OpenCart for use on a multi-language, multi-store project.

We'd like to be able to see in what store an order was placed, just from looking at an invoice number. To do this we'd need to be able to set different invoice number prefixes for all our stores. But OpenCart's admin panel only shows an invoice number prefix setting for my default store.

I worked out how to insert the relevant configuration value directly into the store database, and when I do that, my multi-stores do generate invoices with their own prefix. So I can brute-force the feature already: in a way, the feature's already there, all that needs to be done is to reveal the invoice number prefix option in the admin panel for the multi-stores.

Is there any chance this might be implemented sometime soon?

Thanks!