Concept OK, but...
I don´t have "export" stored in MIs, I use "export" in a block, as you can see:
I don´t know how I can put "export" in MIs, and them how use these MIs in the "File Name" field.
Thinking in the 8 character restriction may be a good idea generare a "20180606" for CSV name. If I put SI33, SI38 and SI38 in consecutive MIs, I can use It?