At 10:38 Friday, 09.08.2002 +1000, you wrote:

>Get hold of a tool such as IB_SQL that shows you the plan after the
>query is prepared and see what's really going on. After that, you can
>start hacking the query to force use of your index.

or IMO even better: get InterBase PLANalyzer from
http://codecentral.borland.com/codecentral/ccweb.exe/listing?id=16721

a great tool that will show you all the details of your queries' plans.

HTH,
Markus