COM2 injection with eco2m eos

I have not been able to find any documentation on how brine injection is handled when using eco2m. NaCl is COM2 in the GENER block. I would assume that salt mass fraction of the brine would be part of determining the correct mass injection rate in this case, for example: 0.1 mass fraction salt would mean that an injection rate of 1 kg/s brine at a node should be modeled as 0.1 kg/s of COM2? But this is not documented anywhere that I can find and would like some clarification if possible, also with regards to handling P/T conditions and injectate properties. I'm using eco2m because of the need for simultaneous CO2 injection elsewhere in the grid. If anyone has some insight it would be appreciated!