MOdicon M221 into Citect SCADA 7.2

Hello,

I need to replace an obsolete twido PLC to Modicon TM2221ME32TK and in the process would like to get the variables back into Citect SACDA V7.2

I have been reading up on REad_var and write_var but am seeking clarification on how to get the existing %MW, digital inputs %I0.0 etc and outputs  %Q0.0 mapped into modbus registers so SCADA can read them. 

I intend to use modbus TCP/IP communcations with the ethernet/ip adaptor. 

Do i need to use read and write_var to map into the addresses?

Please find attached existing PLC code.

PLC.twd