parent report - subreport problem

Hello:
I created a report as a perent report
with subreport in the middle of detail
section of the perent report.
The subreport has a query as the recordsource,
which can return different number of records
depends on input parameter.
My problem is the following:
Depends on the number of records are showing by the subreport
the position of controls on the bottom part of my parent report
is changing every time.
Could you give me a hint how can I make the position of
the bottom part of my report independant
on the number of records in subreport?

Thanks,
GB