Making the Excel File ready only after copy and rename

Greetings!

I've created an SSIS package where it does the following -

1. Import data to Excel file (foo.xlsx) which is in Folder C:\Test

2. Next, that Excel file gets renamed by appending datetime stamp, i.e. foo_201309041800.xlsx

3. Next, that renamed file will be move to a different folder C:\Final

My question is, how can I set the file - foo_201309041800.xlsx to READ-ONLY? Everytime I run the package new files will be copied to C:\Final folder like

foo_201309041800.xlsx

foo_201309041810.xlsx

foo_201309041925.xlsx

Based on my question, all the above files should set to READ-ONLY.

Please let me know if you have any ideas.

Thanks.