How to transmit a D-Bus message with the exact same body?

I'm working on a dbus project where I need to be able to transmit dbus method calls. The idea is: I receive a dbus method call I change the source and destination in order to transmit the message to another object (based on internal logic) The object replies, I take the reply body and I send that back as the reply to the original call I settled on zbus, but its APIs for creating a message and retrieving a message body seem incompatible (the signature isn't constant so I can't deserialize and ...