We have another request for more magnet choices so I am closing this one. You should be able to create a filter in your mail client to override POPFile's classification if it finds your product name in the body.
Magnets cannot guarantee accurate classification. POPFile only learns when reclassifying messages, adding all magnetized messages to the corpus would cause a huge increase its size needlessly.
Eudora starting with version 8 is being based on Mozilla Thunderbird. John did some work was done on creating a POPFile extension to reclassify from inside Thunderbird, but ran into a problem and couldn't make it work.