S2S stream compression with dialback

We have a pair of OpenFire 3.6.3 servers running on Windows 2K3 Server. Regardless of the s2s security and compression settings, we cannot get:

stream compression + dialback

to work for S2S. When we configure Openfire to achieve this s2s communications mode, our packet captures never show stream compression offered in a stream:features stanza between the servers, instead just dialback. However:

TLS (self-signed certiciates) + TLS compression + dialback

TLS (self-signed certificates) + dialback

seem to work just fine. However, we need stream compression + dialback for a particular network path. Any ideas what we could be configuring wrong? Thank you.