American Express Membership Rewards - UK MR Points -> Etihad

Anyone know how to convert miles, or otherwise use UK MR points to book flights with Etihad (apart from Amex TS) e.g. through a partner? It seems BMI code share with Etihad but you can't use BMI miles to book Etihad flights on the code-shared routes.

Also since Brussels is becoming part of Miles & More it seems you can't join and use Etihad rewards through them.... or can you?