In order to synchronize your transponder (XPDR) ident and mode values with swift, you need to enable the SB area (event though your client is swift). Also the feature needs to be enabled by your aircraft, as PMDG or Leonardo do.
If you want to see if you receive data from the SB4 offsets you can use. You can see if the SB4 are is enabled and if data are received. Once data are received packets is > 0 and increasing.
If you want to test the SB4 offsets you can send them via FSUIPC keys for testing. Do NOT get that wrong, you do not FSUIPC for the SB4 XPDR area, but you can use FSUIPC if you want to test swift SB4 integration.