There's no way to know without calling them. And calling them means spending ages on hold - paying per minute - before talking to someone.

I'm pretty sure that only the promo fares (like in email) aren't eligible. The cheapest fare I've seen come up on the web site, doing a normal booking, is R, which qualifies. If you have an ExpertFlyer subscription, you can check the fares there against the prices they show you on aireuropa.com.

This really should work better.