offset for F/O altimeter STD

I use the boeing suite (GC/MCP/CDU).

Hardware aerosoft mcp/efis-left/eicas. For my right efis I interface a real 747 efis panel to fsbus. Everything is functional on that panel except the baro pushbutton that changes the qnh to STD and viceversa.

I experimented with Ox5414 (4 bytes)
ASTI Bit18 (AB STD/QNH push)
ASTO Bit19 (AB STD/QNH pull -> STD BARO 29.92 in)

But no result till now. Anyone implemented this? Is it the right offset?
If anybody did it with fsbus(-CDK) , please post the relevant lines from the ini file.