If you have a set of pre-made detrend images that you want to register into a new database, you can do this with the dettool.
The basic steps are:

 * create a new detRun
 dettool -register_detrend -dbname MD09 -det_type DARK -filelevel fpa -inst GPC1 -telescope PS1
 * register each imfile :
 dettool -register_detrend_imfile -dbname MD09 -det_id 2 -class_id XY01 -uri /data/ipp003.0/rodney/DETREND/DARK/GPC1.DARK_PREMASK.norm.6.1.XY01.fits
  (repeat 60 times)
 * update the detrend state to 'stop'
 dettool -updatedetrun -dbname MD09 -det_id 2 -state stop

The following script, from Gene via Steve, will register a set of detrend images.  Be sure to adjust the database name and directories as appropriate.

<pre>
#!/bin/csh -f

set dbname = MDfakesn
set dir = "/data/ipp003.0/MDfakesn"

# mask
echo "------------------------------------------------------------"
echo "Registering MASKS..."
set subdir = "MASK"
echo "    Running dettool -dbname $dbname -register_detrend -det_type mask -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat"
dettool -dbname $dbname -register_detrend -det_type mask -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat
set detid = `grep " det_id" tmp.dat | awk '{print $3}'`
if ("$detid" == "") then
  echo "failed to register detrend"
  exit 1
endif
foreach f ($dir/$subdir/*.XY??.fits) 
  set class = `echo $f | awk -F. '{print $(NF-1)}'`
  echo "   Running:  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f"
  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f
end
dettool -dbname $dbname -updatedetrun -det_id $detid -state stop

# dark
echo "------------------------------------------------------------"
echo "Registering DARKS..."
set subdir = "DARK"
echo "    Running : dettool -dbname $dbname -register_detrend -det_type dark -filelevel CHIP -inst GPC1 -telescope PS1 -exp_time_min 0.0 -exp_time_max 100000.0 > tmp.dat"
dettool -dbname $dbname -register_detrend -det_type dark -filelevel CHIP -inst GPC1 -telescope PS1 -exp_time_min 0.0 -exp_time_max 100000.0 > tmp.dat
set detid = `grep " det_id" tmp.dat | awk '{print $3}'`
if ("$detid" == "") then
  echo "failed to register detrend"
  exit 1
endif
foreach f ($dir/$subdir/*.norm.*.XY??.fits) 
  set class = `echo $f | awk -F. '{print $(NF-1)}'`
  echo "   Running:  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f"
  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f
end
dettool -dbname $dbname -updatedetrun -det_id $detid -state stop

# flat (r)
echo "------------------------------------------------------------"
echo "Registering rFLATS..."
set subdir = "rFLAT"
echo "    Running : dettool -dbname $dbname -register_detrend -det_type flat -filter r -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat"
dettool -dbname $dbname -register_detrend -det_type flat -filter r -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat
set detid = `grep " det_id" tmp.dat | awk '{print $3}'`
if ("$detid" == "") then
  echo "failed to register detrend"
  exit 1
endif
foreach f ($dir/$subdir/*.norm.*.XY??.fits) 
  set class = `echo $f | awk -F. '{print $(NF-1)}'`
  echo "   Running:  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f"
  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f
end
dettool -dbname $dbname -updatedetrun -det_id $detid -state stop

# flat (i)
echo "------------------------------------------------------------"
echo "Registering iFLATS..."
set subdir = "iFLAT"
echo "    Running : dettool -dbname $dbname -register_detrend -det_type flat -filter i -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat"
dettool -dbname $dbname -register_detrend -det_type flat -filter i -filelevel CHIP -inst GPC1 -telescope PS1 > tmp.dat
set detid = `grep " det_id" tmp.dat | awk '{print $3}'`
if ("$detid" == "") then
  echo "failed to register detrend"
  exit 1
endif
foreach f ($dir/$subdir/*.norm.*.XY??.fits) 
  set class = `echo $f | awk -F. '{print $(NF-1)}'`
  echo "   Running:  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f"
  dettool -dbname $dbname -register_detrend_imfile -det_id $detid  -class_id $class -uri $f
end
dettool -dbname $dbname -updatedetrun -det_id $detid -state stop

exit
</pre>

=== NOTES === 
 * You must leave the detRun.mode as 'register' instead of 'master', so that the system will know that this is a detrend that is registered from the outside, not built from within by the standard tools. 

 * For the DARK, you must include the exp_time_max parameter, because it is required to be non-NULL by the chip processing.