In Spring Integration "channels" (including publish-subscribe-channel) are intra-process while Channel Adapters are inter-process, so a publish-subscribe-channel will send to the subscribers within the same process. Perhaps you can explain your question in a bit more detail, but if you are thinking of "durable subscribers" in the way that JMS topic subscribers can be durable, that's really an issue for inter-process communication - where the consuming process is not running at the same time as the producing process. We do provide JMS Channel Adapters that support such durable Topic subscribers.
Does that help?, and if not, can you elaborate on your question a bit?
subject: Durable pub sub channel in spring integration