double-blind vs single-blind

[baumbach@atmel.com (Peter Baumbach)]

> -------------------------------------------------------------------------
> To find out more about the anon service, send mail to help@anon.penet.fi.
> Due to the double-blind, any mail replies to this message will be anonymized,
> and an anonymous id will be allocated automatically. You have been warned.
> Please report any problems, inappropriate use etc. to admin@anon.penet.fi.

I have a remailer question.

I see a letter posting an offer on the net.
The person making the offer is not anonymous.
I wish to be anonymous, so I decide to use a remailer to reply.
My reply includes a anNNN reply address.
If the original poster replies back, an anonymous id will be allocated to him.

  This isn't any good.  When the reply arrives, I will see the new 
anonymous id of a user whos real username and address I know!  My
pen-pal would compromise his ability to post anonymously in the future.
How can I send an anonymous message that allows a reply that is not
anonymous?

Keep in mind my pen-pal may not know anything about remailers yet.
(I have yet to use them myself :-)

Peter Baumbach
baumbach@atmel.com