Replying to posts from @public.gmane.org?

Switching my newsreader from news.gmane.org to news.gmane.io went very 
smoothly when _reading_ posts, but when I try to reply to a post from 
before the switch on a group that uses the address masking (where all 
the addresses turn into groupname@), the 
messages bounce with:


> ** Address not found **
>
> Your message wasn't delivered to 
>[email protected] because the domain 
>public.gmane.org couldn't be found. Check for typos or unnecessary 
>spaces and try again.
>
>The response was:
>
>DNS Error: 13503541 DNS type 'mx' lookup of public.gmane.org responded 
>with code NXDOMAIN
>Domain name not found: public.gmane.org

I tried manually replacing public.gmane.org with public.gmane.io in the 
message header before sending it, too, but it failed in the exact same 
way.

Is there a workaround for this, or am I doing something wrong? Do I need 
to flush some sort of cache in order to re-download these old messages 
with updated address masks?

-- 
Adrian