If you are sending your ODS output as an attachment, you would be using the second method shown in the FAQ. There does not seem to be a way to rename the file on attach, however, since you control the name of the ODS file that you are going to attach, it should not be a problem to give it the name that you want.
For more information about the "rules" of using the FILENAME EMAIL engine, refer to the Help topic: Sending Electronic Mail from Within the SAS System (EMAIL) or the SAS documentation for your operating system. Note that you may need to change SAS system options related to emailing in order for these techniques to work. Also, if you go to Tech Support and search for the terms 'Email' and 'ODS', there are a lot of hits which describe various issues or troubleshooting tips: