Unfortunately I am still not done with RI.
First of all, for some reason, when I open my database with

OPEN DATABASE ecamat.dbc EXCLUSIVE
MODIFY DATABASE

The "cleanup database" menu item is still not active, and the "edit referential integrity" item answers that the current dbc is not open in exclusive mode. Any idea about what I am doing wrong ?
Then, I can't find the TaxRI builder on the UT downloads, and not with a Google search either.