I've got this one too, and I've also looked at the default vdk30.stp and that conatins all the stop words I could ever use, but it still doesn't seem to get used. On the off chance you got an answer to this I thought I ask before logging a support call?
If you are on 7.2.5. or higher then this should work ok. The .stp file should exclude the word from the search on records like articles but I think there is still an issue with HTML documents. If you are on 7.2.5 or higher and are still getting this issue please raise with support detailing your version.