Automatically mark as paid for manual payment

[unmilk]

Hello,

I have a manual payment method (invoice) and would like to automatically mark all orders as paid that are processed via this payment method:

My fulfillment partner can only receive orders that are marked as paid. 

Is there a A) way to automatically mark all orders as paid, even though it is an automatical payment method?

Or is there B) a way to establish a custom payment method (invoice) as non-manual payment method?

Thanks

[shibbybangbang]

We need this for similar reasons. We've just moved from one inventory system to another but the new one only imports orders when marked as Paid.