Revoking Keys

[Graham]

Recently I generated some keypairs with their relevant revocation 
certificates, but was not able to save my new keyrings before the PC 
crashed :-(

I am therefore dependent on using an old keyring without these new keys 
plus the revocation certificates.  I am not clear exactly how to revoke 
the keys I've generated and now have lost.  I've looked up the man 
pages and the html howto but they just refer to generating a revocation 
certificate and use

revuid

But how do I revoke keys on the keyserver so I can generate new ones?
-- 

Graham