SYSML17 — SysML: Interaction diagram and Data-based comm of SysML

Here is a question on the usage of sequence diagrams with SysML, more specially with blocks that communicate via flow ports. Within UML, Message is associated with signature of either a Signal or an Operation (see constraint 2 on Message meta class, p. 492 of the UML2 superstructure spec.).

In SysML, blocks introduce an alternative for communication between blocks w.r.t. to usual UML2 composite structures: flow ports are basically dedicated to support data-based communication between blocks in contrast of UML2 that does not support such kind of communication between composite structures.
In this case, a Message within an interaction should be able to refer either a DataType, a Block, a ValueType if the communication happen between two atomic flow ports, or to a FlowSpecification if the communication happen between two non-atomic port.

I did not see anything related this issue within the SysML spec. Do I miss something or is it something missing in the SysML doc?

Summary of Problem Statement:
Here is a question on the usage of sequence diagrams with SysML, more specially with blocks that communicate via Ports.

SysML introduces methods of data exchanges with Blocks thru the use of Flow Properties and Interface blocks, which can then be used, to illustrate data exchanges on Sequence Diagrams. On the other hand, UML 2.0 uses Classes, & InformationFlows to convey data exchanges.

Question:
How can data exchange between Part Properties and/or Actors using ValueType, Blocks & Signals be illustrated on a Sequence Diagram, while using Full Ports & Proxy Ports?