No, again this is not correct.
You can never have a Term on the reference pin of the S1P element. It should always be grounded in this sort of application. An S1P data file represents one port data. It is a measure of the impedance or reflection coefficient, however you can think of it most easily, of a complete circuit, including any termination connected to it at the remote end of the circuit, as presented at that single input/output pin. It can never be treated as a through connection, only a load or termination as stated by Volker above. Even the circuit you describe states that "another pin of s1p is grounded" so that is what you should do.