In this case the CSUB and RSUB commands can not be used. Instead, you will have to use the "run" command in direct mode (like the TMCL IDE does to start a program). This is command 129 (it does not have a mnemonic). These commands are listed in chapter 3.34 of the TMCL manual. Your TMCL program in the module should then end with a "STOP" command.
Use the run command with the "type" parameter set to 1 and the "value" parameter set to the address from where you would like to start the program. A TMCL program normally starts at address 0, but you can also start at any other address, e.g. if you would like to define and use more than one function. In this case, use labels and turn on the function "generate symbol file" in the "Options" dialogue of the TMCL IDE (menu "Settings", function "Options"). The TMCL assembler then also geenrates a text file that conatins the address of every label, so that you can take the addresses from there.