Specifying shipping carrier & service

I’m guessing I’m not the first to ask this, but Amazon Help have completely misinterpreted our help request.
In our SellerCentral account, when we receive a book order, we have to specify the shipping carrier and service before confirming dispatch of the order. (We always use Royal Mail). If we don’t specify the carrier and service, then we can’t mark the order as shipped, the customer doesn’t get any confirmation, and if it stays unconfirmed, then I expect we get penalised in some way. That’s fine, and to be expected.

BUT… If it’s an international order, none of Royal Mail’s international services appear in the drop-down list. So, we either have to not confirm the order, because we can’t, or we have to lie about the service we’re using. If we tell the customer that we’ve used (say) Royal Mail 1st Class, instead of RM International Tracked, then he has no way of knowing the book has actually been sent by a tracked service that he can follow.

In other words, Amazon’s system has made it impossible for us to serve our customer satisfactorily. Satisfying Amazon’s requirements leaves the customer misinformed about the shipping method; not satisfying Amazon’s requirements leaves the customer totally uninformed - he’s got no way to tell if the order has been sent or not.

Any suggested way out of this maze?