CouchDB not replicating design documents

I have a CouchDB 1.2.0 instance running on my laptop and I want to replicate a local database named "soup" to a remote machine, which runs a CouchDB 1.1.1 instance. I issue the replication from futon and I can see the request is alright:

Request URL:http://127.0.0.1:5984/_replicate
Request Method:POST
Request Payload: {"source":"soup","target":"http://projects.blurrcat.com/couchdb/soup"}

However, when the replication is done, all documents except the design documents are replicated. Can anyone tell me why? Is it because of the version difference?