eo-* files in datadir and now in tmp

Hi,

does anybody know where these files come from?
We deleted them via cron at night but now our tmp dir is filled up hourly.

Seems these are binary attachments and domino does not delete them
when they are attached or detached from a database?

This is a problem now in 6.54 for us because up to 6.53 these files were 
in the domino data dir but now are in the tmp dir.

Thanks
Rainer