[Mailman-Users] how do I make sure my replies are in the correct thread?

[Greg Rezansoff]

Hello,
  Im trying to participate in a mailman discussion group.

Every time I reply, it creates a new thread!  Its the Vorbis group, so my emails get a [Vorbis] in the subject.

How the heck do I specify the thread I am replying to?

This is extremely frustrating, because its a basic functionality, and I cannot find it in your docs!!!