Posting to foreign group with expired articles

[Frossie]

This may be monumentally stupid, but:

How does one post to a group on a *foreign* server that has no
unexpired articles? Gnus won't let me enter the summary buffer so that
I can just use 'a' and if I am not into the foreign group, typing
nntp+foo.com:some.group on the newsgroup line that I get by using 'a'
in the group summary buffer doesn't seem to do the right thing.


-- 
Frossie