Integration scenrio freezes when I assign a mapping to a connection

Hi,

I'm having an issue with a Integration Scenario I'm trying to modify, basically I've been trying to assign an Interface Mapping to a connection between two actions. The interfaces and message types match up, and the mapping pops up in the list but when I click on apply nothing happens and then the whole thing freezes.

Has anyone seen this before? Could it be a bug, I'm on 7.0 SP 09.

Many thanks,

- Ian