Interfaces, blocks and ports

[Polymorph]

I am new to Enterprise Architect (Rhapsody user). If I create an interface block (in SysML 1.3) and then add a port to a block that implements that interface, I would expect to have access to these operations whenever I place this block on a sequence diagram.

However, when I do this and create a message between this block and an actor, I do not see the operations contained within the interface.

Is this possible?