Getting TimeTaken-Statistics out of RT

Hi all.

We’ve been using RT now for a little over a month to coordinate support
requests, and it has worked really well. But now, after putting a lot of
data in, we have a problem of getting certain data out again.
Since RT also records the time taken for each ticket, we decided to also
use to track time for billing purposes.
To categorize the tickets, we use two sets of Keywords, Customer and
TypeOfReport decides, if this is billable time, and so I need a way to
get a report out of the database, listing the TimeTaken for each
customer, grouped by TypeOfReport. I have been banging my head against
this problem for a few days now, and I can’t figure out how to do this,
so I am asking here, if anybody has succesfully gotten such a report out
of RT.

Thanks in advance,
Alexander Gr�fe